Chapter 14: The Nervous System

The diagnostic examination of the nervous system requires testing of its specific functional components many of which are evaluated while taking the history and examining the body by regions. When evidence of nervous system malfunction is encountered, a complete, systematic neurologic examination is required. The first objective of this systematic examination is to identify all cognitive, sensory, motor, and coordination deficits. From this inventory, the site(s) and mechanism(s) of injury can by hypothesized using the following general principles:

1. Deficits of intellect, memory, or higher brain function imply lesions of the cerebral hemispheres.

2. Deficits of consciousness indicate lesions of the brainstem reticular activating system or bilateral cerebral damage.

3. Paralysis with loss of deep tendon reflexes indicates a lower motor neuron (LMN) lesion interrupting the reflex arc. This can be at the spinal cord, spinal root, plexus or peripheral nerve level. Acute upper motor neuron (UMN) lesions can be associated with decreased reflexes initially, but produce increased reflexes after hours to days.

4. Paralysis with an accentuated deep tendon reflexes (spasticity) indicates an UMN lesion. This may reflect disease of the hemisphere, brainstem, or spinal cord.

5. Unilateral loss of touch and position sensation and contralateral loss of temperature and pain sensation indicate a unilateral lesion of the spinal cord ipsilateral to the loss of touch and position. This happens because the ascending tracts for touch and position sensation decussate in the medulla, whereas the ascending tracts for pain and temperature sensation cross near where they enter the spinal cord.

6. Paralysis is contralateral to lesions above the medulla and ipsilateral below. This is because the descending motor tracts, like the tracts for discriminative sense, decussate in the medulla.

7. An LMN paralysis accompanied by anesthesia in an appropriate distribution usually indicates a peripheral nerve lesion, because many nerves carry both motor and sensory fibers. Sometimes spinal root or segmental cord lesions cause similar signs.

8. Muscle wasting with fasciculation results from an LMN lesion; without fasciculation, wasting is often attributable to intrinsic muscle disease.

Interpretation of the neurologic examination requires a comprehensive understanding of the anatomy and functional organization of the nervous system, which is beyond the scope of this book. The reader should consult anatomy and neurology texts for detailed discussions of neuroanatomy and functional physiology.

Anatomic Organization of the Nervous System

For diagnostic purposes, the nervous system is divided anatomically into the brain, the spinal cord, and the peripheral nerves.

Superficial anatomy of the nervous system

The brain is encased within the rigid skull and the spinal cord within the spinal canal of the vertebral column. The ganglia, plexuses, and nerve trunks are inaccessible to physical examination lying deep to the muscles and bones of the spine, chest, abdomen, and pelvis. The peripheral nerves, however, are distributed in the neurovascular bundles, along with their corresponding arteries and veins, and may be palpable where they exit the trunk and in the extremities.

The central nervous system (CNS)

The brain consists of the cerebrum, the brainstem, and the cerebellum. The cerebrum performs cognitive functions, is the site of emotion and mood formation, and determines personality and behavior. The deep cerebral structures modulate motor and sensory function and control endocrine and appetitive functions. The brainstem consists of the midbrain, the pons, and the medulla and contains nuclei of CN III to CN XII. The cerebellum is involved in many motor and sensory pathways and controls the coordination of complex motor activities.

The spinal cord

It contains the ascending sensory tracts, the descending motor and autonomic tracts, and the LMN which activate skeletal muscles. The dorsal and ventral spinal roots contain the sensory and motor tracts, respectively. The dorsal root ganglia contain the cell bodies of afferent sensory nerves.

The Peripheral Nervous System

The peripheral nervous system is equally complex. Cranial and spinal nerves come together to form ganglia and plexuses (brachial, lumbar, sacral) where the sensory and motor components of the cranial and spinal segments are redistributed into peripheral nerves directed to specific anatomic areas of the periphery.

Functional Organization of the Nervous System

It is also necessary to understand the functional organization of the nervous system. Function can be systematically described as follows: cognition (intellect, language, registration, memory, attention, orientation, spatial discrimination); mood and affect; special sensation (sight, hearing, balance, taste, smell); somatic and visceral sensation (touch, position, pain, temperature, vibration, pressure, two-point discrimination); motor function (pyramidal tracts and extrapyramidal system); posture, balance, and coordination (cerebellar, vestibular, and basal ganglia function); and autonomic function. The autonomic nervous system is divided into the parasympathetic and sympathetic systems. The parasympathetic outflow is from the cranial, cervical, and sacral roots, with ganglia close to the organs they innervate. The sympathetic outflow is from the thoracic and lumbar roots via the sympathetic spinal ganglia.

Mental Status Screening Examination

See Chapter 15 for a complete discussion.

During the history and physical examination, the clinician is evaluating the patient’s mental status. In addition, screening tests like the SLUMS, Mini-Cog, and Mini-Mental State Examination can be used. These are described in Chapter 15. The components of the mental status examination of most interest for neurologic disease are the level of consciousness, memory, and language.

Cranial Nerve (CN) Exam

The 12 pairs of CN emerge from the brain and pass through foramina in the skull base. They are designated by Roman numerals I to XII in relation to their position from forebrain to brainstem. The physical examination of several of the CN is contained in the discussion of the head and neck in Chapter 7.

Olfactory nerve (CN I)

The olfactory mucosa lining the upper third of the nasal septum and the superior nasal concha contains the receptors and ganglion cells. Their fibers converge into approximately 20 branches that pierce the cribriform plate of the ethmoid bone and consolidate to form the olfactory tract.

Testing smell

Evaluate the nasal passages for patency. With the eyes closed, test each nostril while the other is occluded, with familiar odors, such as coffee, cloves, or peppermint.

Optic nerve (CN II)

The optic nerve is actually a tract of the CNS, not a true cranial nerve. It carries afferent impulses from the retina to the Edinger–Westphal nucleus and the visual cortex in the occipital lobes.

Tests for gross visual fields defects

Confrontation Methods: Use a combination of the following tests to detect visual field defects [Kerr NM, Chew SS, Eady EK, Gamble GD, Danesh-Meyer HV. Diagnostic accuracy of confrontation visual field tests. Neurology. 2010;74:1184–1190]. Finger, face, and hand confrontation readily detect temporal field cuts. To detect nasal field cuts, you must test each eye independently.

Finger confrontation

Fingers are presented simultaneously in one quadrant on either side of the midline, testing all quadrants sequentially. The gaze is kept straight ahead at a the examiners nose allowing the examiner to use their visual field as a control. The patient is asked to sum the number of fingers seen. Because it is difficult to differentiate three fingers from four, it is best to use one, two, or five fingers. This testing tells whether there is an absolute defect in one quadrant. You can increase the sensitivity by decreasing the presentation time and increasing the distance from the patient.

Face and hand confrontation

The patient looks at the examiner’s face first with one eye and then the other, and is asked if the face is clear with each eye and if the images are the same. A lack of clarity in one eye or a difference between the eyes suggests a field defect. With hand confrontation, the patient fixes on the examiner’s nose and the examiners hands are held on either side of the vertical midline first above then below the plane of gaze. The patient is asked if the hands appear the same. A cloudy or a faded-color appearing hand represents a relative and subtle defect along the vertical plane.

Color confrontation

This test is traditionally done with red caps of mydriatic bottles. (1) Color comparison about the vertical midline is performed as hand comparison above. This is a very sensitive test for relative hemianopic defects. (2) For central scotoma testing of each eye, the subject is asked to cover the opposite eye and fix their gaze on one red cap just lateral to the axis of gaze, whereas the other is held in their nasal visual field. Ask which cap is redder or brighter. If the peripheral cap is brighter when in fact they are the same color, there is a central scotoma. Do not hold the peripheral cap in the temporal field as a cecocentral defect may confound interpretation; likewise, you might place the cap in the patient’s blind spot.

Kinetic boundary test

Have the patient cover the left eye (Fig. 14-1). Face the patient approximately 1 m (40 in) at the same eye level. Ask the patient to fix constantly on your left eye. Cover your right eye fixing your left gaze on the patient’s unmasked eye. Hold your left hand off to the side in the midplane between your faces. With a flicking finger or penlight for a target, bring it slowly toward the midline between you (Fig. 14-1). Ask the patient to indicate when the target first appears and compare that with your own perception. Also, test vertical and oblique runs. Test the nasal field with your right hand. Test the second eye similarly. This technique is more time consuming and less sensitive and specific than the first three; it is not recommended [Pandit RJ, Gales K, Griffiths PG. Effectiveness of testing visual fields by confrontation. Lancet. 2001;358:1339–1340].

Techniques for uncooperative patients

In obtunded adults, watch for eye movements to novel targets or a blink in response to a threat by an abrupt movement toward the head in each field. If the movement pushes air over the cornea, it will stimulate a corneal reflex that can be misinterpreted as a visual response.

Oculomotor (CN III), trochlear (CN IV), and abducens nerves (CN VI)

CN III is the motor nerve to five extrinsic eye muscles: the levator palpebrae superioris, medial rectus, superior rectus, inferior rectus, and inferior oblique. Its nucleus in the posterior midbrain has a locus for each muscle. CN IV innervates the superior oblique muscle. The CN VI innervates the lateral rectus. These cranial nerves are tested together because they work together to produce the eye movements.

The optical axis of the globe passes from the midpoint of the cornea to the fovea. The globe is suspended at the orbital rim by a fascia that is continuous with the orbital septum and orbital periosteum. This method of floating suspension allows the globe to rotate about three axes intersecting perpendicularly at the center of rotation. The gaze can therefore be directed to any anterior location combining any of these planes. Rotation about the vertical axis through the equatorial plane of the globe permits abduction and adduction; rotation about the horizontal axis through the equator produces elevation and depression; rotation about the optic axis allows intorsion (toward the nose) and extorsion (away from the nose).

Six muscles rotate the globe around the three axes. The four recti originate in a fibrous ring around the optic foramen in the orbital apex (Fig. 14-2); these muscles insert slightly anterior to the global equator, spaced 90 degrees apart; the superior and inferior recti attach to the superior and inferior meridian, whereas the lateral (external) and medial (internal) recti are opposed on the horizontal meridians. The superior oblique muscle originates above the four recti at the optic foramen and then runs anteriorly and medially to the trochlea, a fibrous pulley in the medial side of the anterior orbit, from which it runs laterally and posteriorly under the superior rectus to insert behind the equator in the upper lateral quadrant of the posterior globe. Its physiologic point of action is at the pulley. The inferior oblique muscle originates anteriorly near the medial lacrimal groove, passes posteriorly and laterally between the inferior rectus and the orbital floor to its insertion in the posterior lower lateral quadrant.

In the primary position, the globes are suspended with their optic axes horizontal in the sagittal plane. Because the rectus muscles pull toward the orbital apex, the lateral recti are longer than the medial recti. The superior and inferior recti do not pull exactly in the direction of the optic axis in the primary position (Fig. 14-3A). Study Figure 14-3 to visualize the movement imparted by each of the six muscles starting from the primary position. Contraction of the medial rectus, with relaxation of the opposed lateral rectus, produces adduction; contraction of the lateral rectus and relaxation of the medial rectus results in abduction. Contraction of the superior rectus elevates and intorts the globe because the angular pull produces some rotation about the optic axis. Similarly, the inferior rectus causes depression and extorsion. The superior oblique depresses and intorts, assisting the depression while countering the extorsion of the inferior rectus. The inferior oblique assists the superior rectus in elevation, whereas its extorsion counters the intorting action of the superior rectus. Deviation from the primary position changes the relative effects of various muscles. When the eye is abducted (Fig. 14-3B) so that the pull of the superior and inferior recti coincides with the optic axis, the recti produce pure elevation and depression, respectively. Similarly, adduction can attain a position where the oblique muscles pull along the equator to produce pure elevation and depression without intorsion or extorsion (Fig. 14-3C). Convergence is accomplished by contraction of the two medial recti.

Testing extraocular movements

Ask the patient to indicate if they see double as you test the six cardinal positions of gaze. Have the patient follow your finger to the right, right and up, right and down, to the left, left and up, left and down, and then return to the primary position (Fig. 14-4). When testing horizontally acting muscles, hold the stimulus with the long dimension vertically; for testing vertically acting muscles, hold it horizontally. This allows the patient to more easily see a doubled image. Test convergence by holding the target in the midline and at eye level, approximately 50 cm (20 in.) from the face, gradually moving the target toward the bridge of the nose; note the near point at which convergence fails, normally, 50 to 75 mm (2–3 in.). Finally, test for saccades by having the patient follow your finger as it moves both right–left and up–down. Normally, the eyes track a moving object smoothly; jerky eye movements are saccadic indicating repetitive loss of fixation and refixation. The eyes only move smoothly when tracking a target; this cannot be done consciously.

Trigeminal nerve (CN V)

CN V is the largest CN; it has three divisions. Its sensory root supplies the superficial and deep structures of the face and the deep structures of the head; its motor root innervates the muscles of mastication. The first division, or ophthalmic branch (CN V1), contains sensory fibers from the cornea, ciliary body, conjunctiva, nasal cavity and sinuses, and skin of the eyebrows, forehead, and nose. The second division, or maxillary branch (CN V2), contains sensory fibers from the skin on the side of the nose, the upper and lower eyelids, the palate, and maxillary gums. The third division, or mandibular branch (CN V3) is a mixed nerve with sensory and motor nerves: its sensory fibers are from the temporal region, the external ears, lower lip, lower face, mucosa of anterior two-thirds of the tongue, mandibular gums, and teeth. The motor root supplies the muscles of mastication: masseter, temporalis, and internal and external pterygoid.

Testing the trigeminal nerve

Motor Division: Inspect for muscle wasting in the temporal region, jaw tremor and trismus (spasm of the masticatory muscles). Palpate the temporal and masseter muscles comparing the muscle bulk and tension on the two sides while the patient clenches the teeth (Fig. 14-5A). If there is malalignment of the incisors when the mouth is opened, paralysis of the pterygoid muscle on the weak side is indicated. Sensory Division: With the eyes closed, test light touch, pain and temperature in each division comparing the two sides (Fig. 14-5B). The jaw jerk tests both the motor and sensory components of the trigeminal nerve. Test the corneal reflex by having the patient look upward while you gently touch the cornea (not the sclera) with a small shred of sterile gauze; this normally induces blinking. The corneal reflex is a bilateral reflex testing the fifth and seventh CN on the side stimulated and the seventh consensually.

Facial nerve (CN VII)

The facial nerve contains motor, autonomic, and sensory fibers. It supplies motor fibers to the muscles of the scalp, face, and auricula as well as to the buccinator, platysma, stapedius, stylohyoideus, and the posterior belly of the digastricus. Autonomic motor fibers in the chorda tympani nerve, a branch of CN VII, supply the submandibular and sublingual salivary glands. CN VII carries sensation from the ear canal and behind the ear and taste on the anterior two-thirds of the tongue.

Testing the facial nerve

Motor: Inspect the face in repose for paralysis or spasm. Have the patient perform the tasks below to detect asymmetry indicating unilateral paralysis and to determine whether the cause is an LMN or an UMN lesion: (1) inspect the face in repose noting the palpebral fissures, nasolabial folds and corners of the mouth; (2) elevate the eyebrows and wrinkle the forehead or have them look up and inspect the forehead wrinkles; (3) frown; (4) tightly close the eyes; (5) show the teeth; (6) whistle and puff the cheeks; and (7) smile. Sensory: Test taste on the anterior two-thirds of the tongue with sugar, vinegar (dilute acetic acid), quinine, and table salt. Write the words sweet, sour, bitter, and salty on a piece of paper and have the patient identify the sensation. Holding the tongue in gauze, touch the anterior two-thirds successively on one side then the other with an applicator saturated with the test substance. Remember, sweet receptors are located on the tip of the tongue. Get the patient’s response before testing the other side. Have the patient rinse the mouth with water between tests.

Acoustic nerve (CN VIII)

The eighth nerve is a relatively short trunk consisting of the cochlear and vestibular sensory nerves. They are morphologically and functionally distinct. The cochlear nerve supplies the organ of Corti, whereas the vestibular nerve furnishes sensory endings for the semicircular ducts.

• Testing the cochlear portion (hearing). See Chapter 7.

• Testing vestibular function (balance). See Chapter 7.

Glossopharyngeal nerve (CN IX)

CN IX contains sensory, motor, and autonomic fibers. The sensory nerves are for pain, touch, and temperature from the mucosa of the pharynx, fauces, and palatine tonsil; and it is the taste nerve from the posterior third of the tongue. Somatic motor fibers travel through both the glossopharyngeal and vagus to innervate the pharyngeal muscles.

Testing the glossopharyngeal nerve

This is tested with the vagus nerve, below.

Vagus nerve (CN X)

The vagus carries motor, sensory, and autonomic fibers to and from the neck, thorax, and abdomen. It exits the skull in the jugular fossa. Its cervical branches are the pharyngeal, superior laryngeal, recurrent laryngeal, and superior cardiac nerves. The thoracic branches are the inferior cardiac, anterior and posterior bronchial, and esophageal nerves. The major abdominal branches are the gastric and hepatic nerves, and the celiac and superior mesenteric ganglia.

Testing glossopharyngeal and vagus nerves

Listen for voice quality and normal variations of tone. Pharynx: While inspecting the pharynx, have the patient say “ah,” noting elevation of the uvula. Note whether the faucial pillars converge equally. Test the gag reflex by touching the back of the tongue with a tongue blade. Test the pharyngeal mucosa for areas of anesthesia by touching with an applicator. Larynx: Watch the laryngeal contours in the neck to see if they rise with swallowing (Fig. 14-5D). Have the patient swallow water observing for coughing or reflux into the posterior nose. Examination of the vocal cords is described in Chapter 7 on Examination of the Larynx.

Accessory nerve (CN XI)

The accessory nerve is the motor nerve to the trapezius and sternocleidomastoid muscles.

Testing the accessory nerve

Palpate the upper borders of the trapezii while the patient raises his shoulders against resistance. Look for scapular “winging” as the patient leans against a wall with palms and arms extended. Test the strength and the bulk of the sternocleidomastoid by having the patient turn his head to one side then attempt to bring his chin back to the midline against resistance (Fig. 14-5E).

Hypoglossal nerve (CN XII)

The hypoglossal is the motor nerve to the tongue.

Testing the hypoglossal nerve

Inspection for fasciculations and wasting is done with the tongue at rest in the floor of the mouth. Fasciculations may be normal when the muscles contract to protrude the tongue. When one side is paralyzed, the tongue protruded tongue deviates toward the weak side (Fig. 14-5F). Test muscle strength by having the patient push the tongue against the cheek while your hand resists from the outside. Test lingual speech by having the patient repeat “La, La, La”.

K, L, M test for dysarthria

To parse cranial nerve deficits causing dysarthria, ask your patient to say: “Ka, Ka, Ka” (gutturals, CN IX and CN X); “La, La, La” (linguals, CN XII); and “Me, Me, Me” (labials, CN VII).

Motor Examination

Normal motor function requires that the skeleton, muscles, and motor nerves (pyramidal and extrapyramidal) are intact. Assessing muscle movements requires joint motion; hence the orthopedic, rheumatologic, and neurologic examinations are interdependent.

Inspecting for Muscle Wasting

Evaluation for wasting is done by comparing the muscle masses side to side and the relative masses in different regions.

Evaluating Muscle Tone

With the patient relaxed, assess muscle tone by resistance to passive range of motion. You may need to divert the patient’s attention to relax the muscles. Gently rocking or lifting a limb and letting it fall reveals the tone. When the patient sits on the exam table the freedom of dangling leg swing indicates their tone.

Testing Muscle Strength

Have the patient actively move the joint through its range of motion. Then have the patient try moving against resistance while you palpate the contracting muscle (Fig. 14-6). If the limb cannot move against gravity, position it to move unaffected by gravity. An arbitrary scale is used for grading muscle strength.

Grading muscle strength (Oxford Scale)

Grade 0—No muscle movement.

Grade 1—Muscle movement without joint motion.

Grade 2—Moves with gravity eliminated.

Grade 3—Moves against gravity but not resistance.

Grade 4—Moves against gravity and light resistance.

Grade 5—Normal strength.

Lower extremity muscle strength usually exceeds the examiner’s arm strength, so mild leg weakness is easily missed with resisted motion. Therefore, the following tests are useful. (1) Watch the patient get up after sitting on the floor. Use of both arms and raising the buttocks first by working the hands on the floor toward the feet and then up the legs, indicates proximal muscle weakness (Gowers sign). (2) Ask the sitting patient to stand without using their arms for assistance; if they do this easily, see if it can be done one leg at a time using the hands only for balance. (3) Have the patient hop on the balls of the feet, then on each foot individually. Normally, the heel will not strike the ground. Having the patient hop on a piece of paper will accentuate the sound of the heel strike (creating a “gallop” rhythm), indicating gastrocnemius and soleus muscle weakness.

Examination of reflexes

In the screening examination, the clinician usually tests a few reflex arcs, representative of various levels in the spinal cord and brainstem. A normal reflex confirms the integrity of each element in the reflex arc and proper function of the descending motor tracts. When an abnormality is encountered, lesions can be localized by mapping the normal and abnormal reflexes to their spinal cord and brainstem levels.

Brainstem Reflexes

These are tested during CN examination. The CN innervations of the afferent and efferent limbs are shown in parentheses.

Direct pupillary reaction to light

The iris constricts when bright light is shone on the retina (afferent CN II; efferent ipsilateral CN III).

Consensual pupillary reaction to light

Light stimulation of one retina produces constriction of the contralateral pupil (afferent CN II; efferent contralateral CN III).

Ciliospinal reflex

Pinching the skin on the back of the neck causes the pupils to dilatate (afferent cervical somatic nerves; efferent cervical sympathetic chain).

Corneal reflex

Touching the cornea causes blinking of the eyelids (afferent CN V; efferent CN VII).

Jaw reflex

When the mouth is partially open and the muscles relaxed, tapping the chin closes the jaw. The reflex center is in the mid-pons (afferent CN V; efferent CN V).

Gag reflex

Gagging occurs when the pharynx is stroked. The reflex center is in the medulla (afferent CN IX, -X; efferent CN IX, -X).

The Muscle Stretch Reflexes

Muscle stretch reflexes are often misnamed “tendon” reflexes. The muscle is stretched by a brisk tap on its taut tendon of insertion. The muscle stretch reflex is a simple reflex arc containing a muscle cell, a sensory, and a motor neuron (Fig. 14-7). A diminished or absent reflex indicates an interrupted reflex arc. When the descending motor pathway (the pyramidal tract) in the spinal cord is injured above the level of the reflex arc, normal cortical inhibition is lost, producing a hyperactive or spastic reflex. General principles for eliciting muscle stretch reflexes: The limb should be relaxed. Identify the tendon of the muscle to be tested. Position the limb so that the muscle is slightly stretched. Strike a brisk blow on the tendon with the finger or reflex hammer; if the tendon cannot be struck directly, place your thumb on the tendon and strike your thumb. If no reflex is present, reinforcement can be used: have the patient concentrate on a voluntary act such as pulling on interlocked fingers or clenching the fists while you test the reflex.

There is considerable variability in normal reflexes, from absent to brisk. Significant asymmetry between right and left at the same level is abnormal. Clonus, the sustained repetitive maintenance of the reflex arc with tonic stretch of the muscle is always abnormal. A four-point scale, denoted by numbers or pluses, is commonly used to grade the reflex response.

0, 0 No response

1, + Detectable only with reinforcement

2, + + Easily detectable

3, + + + Brisk with at most a few beats of clonus

4, + + + + Sustained clonus

The reflexes below are listed by descending level of the reflex center in the spinal cord. The peripheral nerves carrying the afferent and efferent signal are listed in parentheses.

Reflex center at C5 to T1: pectoralis reflex (medial and lateral anterior thoracic nerves)

Support the arm in 10 degrees of elevation at 90 degrees of abduction (Fig. 14-8A). Place the fingers of your left hand on the patient’s shoulder with your thumb extended downward pressing firmly on the tendon of the pectoralis major. Strike a blow directed upward toward the axilla. The muscle contraction can be seen or felt.

Reflex center at C5 to C6: biceps reflex (musculocutaneous nerve)

Place the elbow at 90 degrees of flexion with the arm slightly pronated. Grasp the elbow with your left hand so that the fingers are behind and your thumb presses the biceps tendon (Fig. 14-8B). Strike a series of blows on your thumb varying your thumb pressure with each blow until the most satisfactory response is obtained. The normal reflex is elbow flexion.

Reflex center at C5 to C6: brachioradialis reflex (radial nerve)

Hold the patient’s wrist with your left hand with the forearm relaxed in pronation (Fig. 14-8C). With a vertical stroke, tap the forearm directly, just above the radial styloid process. The normal response is elbow flexion and forearm supination.

Reflex center at C6 to C7: pronator reflex (median nerve)

Hold the patient’s hand vertically so the wrist is suspended (Fig. 14-8D). From the medial side, strike the distal end of the radius directly with a horizontal blow. The normal response is pronation of the forearm. Alternatively strike the distal end of the ulna directly with a blow mediad.

Reflex center at C7 to C8: triceps reflex (radial nerve)

Hold the patient’s arm at 90 degrees abduction and elevation, allowing the relaxed forearm to dangle with the elbow at 90 degrees flexion (Fig. 14-8E). Tap the triceps tendon just above the olecranon process. The normal response is elbow extension. Alternatively, have the patient flex both elbows, bringing the arms parallel across the chest (Fig. 14-8E). Have each hand grasp the other forearm. Reinforcement can be obtained by having the patient grasp harder and extending the elbow slightly.

Reflex center at T8 to T9: upper abdominal muscle reflex

Tap the muscles directly near their insertions on the costal margins and xiphoid process (Fig. 14-9A).

Reflex center at T9 to T10: middle abdominal muscle reflex

Stimulate the muscles of the mid-abdomen by tapping an overlaid finger or doubled-tongue blades (Fig. 14-9B).

Reflex center at T11 to T12: lower abdominal muscles

Tap the muscle insertions directly, near the symphysis pubis (Fig. 14-9C).

Reflex center at L2 to L4: quadriceps reflex (femoral nerve)

Several methods are available. In each, a normal response is extension of the knee and contraction of the quadriceps can be palpated. Legs Dangling (Fig. 14-10A): Grasp the lower thigh with your left hand, then tap the patellar tendon. Sitting, Feet on the Floor (Fig. 14-10B): The patient sits on a chair or low bed with the toes curled in plantar flexion and knee slightly extended from a right angle. Tap the patellar tendon directly. Lying Supine (Three Methods): Method 1—With your hand under the popliteal fossa, lift the patient’s knee from the table. Tap the patellar tendon directly (Fig. 14-10C). Method 2—Grasp the patient’s foot, flexing the hip and knee, and rotate the knee outward and dorsiflex the foot. Tap the patellar tendon directly (Fig. 14-10D). Method 3—With the knee extended and the leg lying on the table and your index finger on the quadriceps tendon insertion, push the patella distally. Tap downward on the index finger (Fig. 14-10E). The muscle contraction pulls the patella proximally.

Reflex center at L2 to L4: adductor reflex (obturator nerve)

With the patient supine, place the limb in slight abduction (Fig. 14-11A). Directly tap the adductor magnus tendon just proximal to its insertion on the medial epicondyle of the femur. Normally, the thigh adducts. An absent quadriceps reflex and normal adductor reflex indicates a femoral nerve lesion.

Reflex center at L4 to S2: hamstring reflex (sciatic nerve)

Have the patient supine with hips and knees flexed at about 90 degrees and the thighs rotated slightly outward. Place your left hand under the popliteal fossa so the index finger compresses the medial hamstring tendon (a bundle of tendons from semitendinosus, semimembranosus, gracilis, sartorius) (Fig. 14-11B). Tap your finger. The normal response is flexion of the knee and contraction of the medial mass of hamstring muscles. Test the lateral hamstrings in a similar manner: with your finger compress the lateral hamstring tendon just proximal to the fibular head and tap your finger. The normal response is contraction of the lateral hamstring mass (biceps femoris) and flexion of the knee.

Reflex center at L5 to S2: Achilles reflex (tibial nerve)

Assess both the contraction and relaxation of the muscle. The normal response is contraction of the gastrocnemius and plantar flexion of the foot; delayed relaxation (hung-up reflex) is characteristic of hypothyroidism. Legs Dangling (Fig. 14-11C): With your left hand, grasp the patient’s foot and pull it into dorsiflexion to find the amount of Achilles stretch that produces the optimal response. Tap the tendon directly. Kneeling (Fig. 14-11C): Have the patient kneel with the feet hanging over the edge of a chair, table, or bed. With your left hand dorsiflexing the foot, tap the tendon directly. Supine (Fig. 14-11C): Partially flex the hip and knee while rotating the knee outward as far as comfort permits. With your left hand, grasp the foot and pull it into dorsiflexion, then tap the Achilles tendon directly.

The Superficial (Skin) Reflexes

These reflex arcs have receptors in the skin rather than in muscle fibers. Their adequate stimulus is stroking, scratching, or touching. If there is no response, a painful stimulus can be tried. The superficial reflexes are lost in pyramidal tract disease.

Reflex center at T5 to T8: upper abdominal skin reflex

Have the patient supine and relaxed, with the arms at the sides and knees slightly flexed. Stroke the skin over the lower thoracic cage from the midaxillary line toward the midline (Fig. 14-12A). Watch for ipsilateral contraction of the muscles in the epigastric abdominal wall. When the muscle contractions cannot be seen, look for umbilical deviation toward the stimulated side. In very obese persons, retract the umbilicus toward the opposite side to feel it pull toward the side of stimulation.

Reflex center at T9 to T11: mid-abdominal skin reflex

Stroke the skin from the flank toward the midline at the umbilical level.

Reflex center at T11 to T12: lower abdominal skin reflex

Stroke the skin from the iliac crests toward the midline of the hypogastrium.

Reflex center at L1 to L2: cremasteric reflex

In males, stroke the inner thigh from the inguinal crease downward (Fig. 14-12B). Normally, this causes cremaster contraction with prompt elevation of the testis on that side. A slow and irregular rise of the testis results from muscular contraction in the dartos tunic and is not the reflex response.

Reflex center at L4 to S2: plantar reflex

Grasp the patient’s ankle with your left hand. With a blunt point and moderate pressure, stroke the sole near its lateral border, from the heel toward the metatarsal heads, where the course should curve medially following the bases of the toes (Fig. 14-12D). For the blunt point, use a wooden-tip applicator, the end of a split wooden tongue blade, or the dull handle end on a reflex hammer. If no response is observed, a pin should be used as this is a nociceptive reflex. Normally, this produces plantar flexion of the toes and, often, the entire foot. With pyramidal tract disease some or all of four components of the reflex may be seen: great toe dorsiflexion, fanning of all toes, ankle dorsiflexion, and knee and thigh flexion. This is Babinski sign; it should be recorded as present or absent.

Reflex center at S1 to S2: superficial anal reflex (anal wink)

Stroke the perianal skin and the anal sphincters contract.

Posture, Balance, and Coordination—The Cerebellar Examination

Precise voluntary movement requires graded contraction of the agonist, or prime mover, with a corresponding graded relaxation of the antagonist about each joint. Other muscles act to fix the joint. The total integration of these movements, called coordination, is partially mediated through efferent and afferent cerebellar tracts. The vestibular apparatus and the cerebral cortex also participate. Maintenance of posture and balance requires sensory input from the joints, muscles, tendons, and vestibular system, and coordinated motor outputs mediated by the cerebral cortex and basal ganglia.

Testing Station

Ask the patient to stand comfortably with the arms at the sides (Fig. 7-16). Observe the position of the feet. Normally, the feet will be just a few centimeters apart and the knees opposed. A wide stance suggests an accommodation to instability of stance. Next, have the patient put the feet together and observe for stability. Note swaying of the trunk or elevation of the arms to maintain balance. Now, have the patient close her eyes while observing for loss of balance. Be ready to support her should she lose her balance and reassure her you will protect her. Loss of balance during the test is the Romberg sign. If she remains stable, tell her you are going to push her gently to assess her stability. Gently push her laterally on each upper arm, forward on the upper back and, last, backward on the chest. With normal proprioception, vestibular function, and cerebellar and motor pathways she will remain stable throughout. After fair warning, with her eyes open, push more firmly on her chest to check for maximal stability.

Testing for Diadochokinesia

Coordinated movements require the ability to arrest one motion and initiate its opposite. Loss of this ability (dysdiadochokinesia) is characteristic of cerebellar disease. Many simple tests can be used to test for dysdiadochokinesis. Alternating Movements (Fig. 14-13) (1) Have the patient hold his forearms vertically and alternate pronation and supination in rapid succession. In cerebellar disease, the movements overshoot, undershoot, or are irregular and inaccurate; the motions may be slowed or incomplete in disease of the pyramidal tract. (2) Have the patient rapidly tap his fingers on the table, or close and open the fists. (3) Holding the arms at 90 degrees elevation and 0-degree abduction may show the affected arm deviating in abduction. (4) While the patient clenches his fist with elbow flexed and forearm pronated, grasp his fist from above and pull strongly attempting to extend his elbow against his resistance; suddenly release your grip and observe for rapid control of rebound (Stewart–Holmes Rebound Sign, Fig. 14-13). The examiner must guard against injury to the patient. With cerebellar disease, the forearm may rebound in several cycles of extension-flexion; the patient may strike himself if not guarded.

Testing for Dyssynergia and Dysmetria

Finger-to-Nose Test: With the eyes open, have the patient fully extend his elbow and, in a wide arc, rapidly bring the tip of the index finger to the tip of his nose (Fig. 14-13B). In cerebellar disease, this is attended by an action tremor. Attempting this with the eyes closed evaluates position sense in the shoulder and elbow. A variation is to have the patient make wide arcs with both arms to touch the tips of his index fingers in front of him. Heel-to-Shin Test: With the patient supine and the lower limbs resting in extension, ask the patient to raise one heel and place it on the opposite knee, then slide the heel down the shin (Fig. 14-13C). The foot should be dorsiflexed, and the motion should be performed slowly and accurately. In cerebellar disease, the arc of the heel to the knee is jerky and wavering, the knee is frequently overshot, and the slide down the shin is accompanied by an action tremor. With the eyes closed, the motions are inaccurate in posterior spinal column disease. Frequently, the heel slides off the shin, but action tremor is absent.

Evaluating Gait

Gait is influenced by the rate, rhythm, and character of the individual movements employed in walking. Before assessing the neurologic contribution to gait, painful and restrictive conditions of the joints, muscles, and other structures must be excluded. Observe the patient’s gait in a well-lighted hallway. Note the head, neck and trunk posture, swing of each arm, leg swing, width of stance, step size, and clearance of the toe from the floor. Be sure to observe all three phases of gait: touch down, which should occur with the lateral heel; stance, which should be centered; and push-off which should come off the great toe. Foot strikes are normally in a nearly straight line. Also, observe a turn for loss of balance or multiple small steps to get turned around. Next, have the patient walk away from you on the toes, observing from behind, turn and walk toward you on the heels observing from the front; note how far the heels and toes, respectively, are held off the ground. Examine wear on the patient’s shoes; abnormal wear patterns are a good clue to disorders of the foot and gait.

Testing Past Pointing

Have the patient sit facing you, pointing his forefingers toward you with his eyes closed (Fig. 7-15). Place your forefingers lightly under his and hold them there. Ask the patient to raise his arms and hands, and then return his fingers to yours. Normally, this maneuver can be performed accurately. Past pointing indicates either loss of positional sense or labyrinthine stimulation.

Other tests of labyrinth function are described in Chapter 7.

Testing Skilled Acts

Ask the patient to write a sentence to inspect handwriting. Test his facility at buttoning and unbuttoning a coat or shirt. Have him pick up pins or thread a needle. Test his skill at cutting figures out of paper with scissors.

Sensory examination

A complete assessment of sensory modalities is not made during the routine physical examination. A history of diabetes, localized pain, numbness, or tingling, or the finding of motor deficits, calls for a detailed sensory examination.

The patient must be lucid and have adequate attention to cooperate with the examination. The clinician must have a detailed knowledge of segmental and peripheral nerve distribution in the skin (refer to Figs. 14-14 and 14-15) and make a drawing of the distribution of sensory deficits. The diagram may be used for immediate comparison on retesting; abnormal sensory examinations should be repeated for consistency, progression or resolution. Disparities in examinations may indicate factitious findings.

The detailed cranial nerve exam includes testing of the special senses and the cutaneous sensation of the head. For the remainder of the body, the distribution of sensibility for cutaneous pain, touch, pressure, position, and vibration should be evaluated. If a deficit in pain sensation is detected, temperature sensation must be tested. When an area of altered cutaneous sensibility is found, the borders should be marked with a skin pencil, and a diagram recorded in the patient’s record.

Testing Superficial Pain—Sharp-Dull

Sensibility to pain may be increased (hyperalgesia), normal, reduced (hypalgesia) or absent (analgesia). Have the patient close his eyes. The skin is stroked lightly with the point of a sterile pin and asked if the sensation is painful (Fig. 14-16A). Observe the patient’s facial expression for signs of discomfort. If there is doubt about the response, mix sharp and dull stimuli from the point and head of the pin. Compare side-to-side with the same degree of pressure; it is better if the patient reports differences than if you suggest them. In mapping deficit borders, slowly stimulate the skin from nonsensitive to sensitive skin, having the patient indicate where the sensation changes.

Testing Deep Pain

Test for deep or protopathic pain by pressure on the nerve trunks, and tendons. For example, in the Abadie sign for tabes dorsalis, the normal pressure tenderness of the Achilles tendon is lost.

Testing Temperature Sense

When pain sense is impaired, test for temperature sensibility; the pathways are closely associated. Ask the patient to distinguish between warm and cold. With the eyes closed, touch the skin with glass tubes of hot and cold water. Alternatively, test cold perception with a cold tuning fork and warm perception by exhaling on the skin through your widespread lips.

Testing Tactile Sense

With the eyes closed, compare sensation right to left by stroking the skin with a shred of sterile gauze. Have the patient indicate when and where you touch him. If you suspect that he is using his eyes, make sham tests near but without touching the skin. Grade the results as hyperesthetic, normal, hypesthetic, or anesthetic.

Testing Proprioception (Position Sense)

With the patient’s eyes closed, grasp a finger on the sides (avoid grasping on the top and bottom or touching adjacent fingers because that provides touch cues). Extend or flex the finger at one joint and ask the patient to state its position (Fig. 14-16B). Similarly, test the position sensation in the metatarsophalangeal joint of the great toe. Normal young patients discriminate 1 to 2 degrees of movement in their distal finger joints and 3 to 5 degrees of the great toe. Test position sense in the leg or arm with the eyes closed. Place one limb in a position and ask the patient to place its counterpart in a symmetrical position.

Testing Vibration Sense (Pallesthesia)

Place the handle of a vibrating 128-Hz tuning fork over bony prominences, such as the radial styloid, the subcutaneous aspects of the tibiae, the ankle malleoli, or the great toe interphalangeal joint (Fig. 14-16C). Compare symmetrical points. When the patient indicates that the vibration of the fork has ceased, place the handle on your own wrist to detect any persistence of vibration. Make sham tests by setting the fork in vibration and unobtrusively stopping it with your finger before applying the handle to the patient.

Testing Pressure Sense

Standardized monofilaments are available to precisely check for protective pressure sensation. Anesthesia to a 10-g monofilament is a sensitive test for loss of protective sensation to pressure injury. All diabetics should be tested at least once a year with this technique [Caputo GM, Cavanagh PR, Ulbrecht JS, Gibbons GW, Karchmer AW. Assessment and management of foot disease in patients with diabetes. N Engl J Med. 1994;331:854–860]. Test the patient’s ability to discriminate objects of different weight in their palms. Test the ability to distinguish between pressures from the head of a pin and the tip of your finger. Press over the joints and subcutaneous aspects of bones for perception of pressure.

Testing Higher Integrative Functions

Testing stereognosis

Simple sensory perception must be normal. With the eyes closed, test the ability to identify objects placed in the hands. Use coins, pencils, glass, wood, metal, cloth, and other familiar articles.

Testing two-point discrimination

Test the ability to distinguish the separation of two simultaneous pinpricks as the stimuli are moved farther apart (Fig. 14-16D). Find the distance at which two points rather than one are identified. Test and compare symmetric regions. The normal distance varies in different parts of the body, from 1 mm on the tongue, to 2 to 8 mm on the fingertips, 40 mm on the chest and forearm, and 75 mm on the upper thigh and upper arm.

Testing graphesthesia

Tell the patient you will write numerals or letters “right-side up” on the skin. Then, while their eyes are closed, ask the patient to identify figures 1 cm high traced with a blunt point on the distal pad of the index finger. The figures should be at least 2 cm high on other body parts.

Testing Specific Peripheral Nerves

Exclusion test for major nerve injury in the upper limb

Normal sensibility to pinprick in the index and little fingertips excludes major injury to the median and ulnar nerves. Normal extension of the thumb and fingers excludes radial nerve injury (Fig. 14-17).

Testing the median nerve

Motor Function: Have the patient clasp the hands firmly together; the index finger cannot flex when the innervation of the flexor digitorum sublimis has been injured anywhere below the antecubital fossa (Ochsner Test, Fig. 14-18A). Thumb Flexion (Fig. 14-18B) Hold the patient’s first metacarpophalangeal joint with your thumb and index fingers so that the metacarpal bone is extended and ask the patient to bend the interphalangeal joint; failure indicates paralysis of the flexor pollicis longus, innervated by the volar interosseus that branches from the median nerve in the middle third of the forearm. Thumb Abduction Testing the abductor pollicis brevis, innervated exclusively by the median nerve, distinguishes median from low-level ulnar nerve paralysis: (1) Wartenberg Oriental Prayer Position (Fig. 14-18C). Have the patient extend and adduct the four fingers of each hand, with thumbs extended, then raise the two hands in front of the face so they are side by side in the same plane, with thumbs and index fingers touching tip to tip. Paralysis of the abductor pollicis brevis prevents full range of thumb abduction, so thumbs do not come together when index fingers touch. (2) Pen-Touching Test (Fig. 14-18D). Have the patient rest the supinated hand on a table holding the fingers flat. Ask the patient to raise his thumb in straight up off the table to touch a pen or pencil held horizontally above the thumb. Sensory Function: Test touch, two-pont, and sharp-dull on the thumb, index, middle, and fourth finger, and palm; compare right to left (Fig. 14-18E). Decreased or absent sensation indicates a lesion in the median nerve.

Testing the ulnar nerve

Motor Function: Weakness of finger adduction results from paralysis of the interosseus palmaris demonstrated by pulling a sheet of paper from between the patient’s extended and adducted fingers to assess the pressure exerted by the sides of the fingers (Fig. 14-19A). Paralysis of the adductor pollicis can be tested by asking the patient to grip each end of a folded paper between thumbs on top and index fingers underneath. Have the patient pull the hands apart while gripping the paper. The thumb with an inadequate adductor flexes at its interphalangeal joint from involuntary use of the flexor pollicis longus, innervated by the median nerve (Fig. 14-19B). With lesions at or below the elbow, test for paralysis of the flexor carpi ulnaris. Lay the supinated hand on the table holding all but the little finger flat against the table. Have the patient abduct the little finger maximally; if there is no paralysis, the tensed tendon may be seen or palpated at the wrist (Fig. 14-19C). Sensory Function: An area of anesthesia covers the ulnar digits and the corresponding region of the palm. A similar distribution occurs on the back of the hand. When the nerve lesion is at the wrist the anesthesia is only on the distal half of the little finger (Fig. 14-19D).

Movements of specific muscles and nerves

It is frequently desirable to identify the muscles and nerves involved in a movement deficit. The following is a compilation of the principal muscle movements, the muscles involved, and their innervation (in parentheses). This survey starts with CN and precedes distally identifying movements served by cervical, thoracic, lumbar, and sacral roots sequentially. The reader can trace an abnormal movement to the peripheral nerve and spinal root or a deficit can be predicted for each peripheral nerve or spinal segment.

• Eyebrow, elevation. Frontalis (CN VII from inferior pons).

• Eyebrow, depression downward and inward, wrinkling of the forehead. Corrugator (CN VII from inferior pons).

• Upper eyelid, elevations. Levator palpebrae superioris (CN III from upper midbrain).

• Eyelids, closing, wrinkling of forehead, compression of lacrimal sac. Orbicularis oculi (CN VII from inferior pons).

• *Eyeball, elevation and adduction. Superior rectus (CN III from upper midbrain).^1*

• ^*Ophthalmologic Interpretation of Muscle Action. The items marked with asterisks constitute the actions of the oculorotatory muscles, as assigned by the anatomists and some neurologists. Sharply divergent interpretations are furnished by the ophthalmologists on the basis of clinical findings. The direction of movement of the eyes is a result of the actions of synergists and antagonists producing six cardinal positions of gaze, corresponding to the six extraocular muscles. Paralysis of a single muscle results in the inability of the eye to attain its cardinal position, which, in four of the six muscles, does not correspond to the prediction of the anatomists.

• *Eyeball, elevation and outward rotation. Inferior oblique (CN III from upper midbrain).

• *Eyeball, depression and rotation downward and inward. Inferior rectus (CN III from upper midbrain).

• *Eyeball, depression and rotation downward and outward. Superior oblique (CN IV from midbrain) or primary downward rotation, secondary inward (intorsion) rotation, and tertiary weak outward rotation.

• *Eyeball, adduction. Medial rectus (CN III from upper midbrain).

• *Eyeball, abduction. Lateral rectus (CN VI from inferior pons).

• Pupil, constriction. Ciliary (CN III and parasympathetic from upper midbrain).

• Lips, retraction. Zygomatic (CN VII from inferior pons).

• Lips, protrusion. Orbicularis oris (CN VII from inferior pons).

• Mouth, opening. Mylohyoid (CN V from pons), digastricus (CN VII from pons).

• Mandible, elevation and retraction. Masseter and temporalis (CN V from mid-pons).

• Mandible, elevation and protrusion. Pterygoid (CN V from mid-pons).

• Pharynx, palatine elevation and pharyngeal constriction. Levator veli palatini and pharyngeal constrictor (CN IX and X from medulla).

• Tongue, depression and protrusion. Genioglossus (CN XII from medulla).

• Neck, rotation of the head. Sternocleidomastoid and trapezius (CN XI from medulla and upper cervical cord).

• Neck, flexion. Rectus capitis anterior (C1 to C3).

• Neck, extension, and rotation of the head. Splenius capitis et cervicis (C1 to C4).

• Neck, lateral bending. Rectus capitis lateralis (C1 to C4 and suboccipital nerve).

• Spine, flexion. Rectus abdominis (T8 to T12).

• Spine, extension. Thoracic and lumbar intercostals (thoracic nerves from T2 to L1).

• Spine, extension and rotation. Semispinalis (thoracic nerves from T2 to T12).

• Spine, extension and lateral bending. Quadratus lumborum (lumbar plexus from T10 to L2).

• Ribs, elevation and depression. Scaleni and intercostal (cervical and thoracic nerves from C4 to T12).

• Ribs, elevation. Serratus posterior superior (from T1 to T4).

• Diaphragm, elevation and depression. The diaphragmatic muscles (phrenic nerve from C3 to C5). Remember diaphragmatic innervation by the phrenic nerve with the rhyme, “C3, 4, and 5 to keep the man alive.”

• Scapula, rotation and extension of neck. Upper trapezius (CN XI from C3 to C4).

• Scapula, retraction with shoulder elevation. Middle and lower trapezius (CN XI from C3 to C4).

• Scapula, elevation and retraction. Rhomboids (dorsal scapular nerve from C5).

• Arm, elevation. Supraspinatus (suprascapular nerve from C5 to C6), upper trapezius (CN XI from C3 to C4).

• Arm, elevation and rotation. Deltoid (axillary nerve from C5 to C6).

• Arm, depression and adduction. Middle pectoralis major (anterior thoracic nerve from C5 to T1).

• Arm, depression and medial rotation. Subscapularis (subscapular nerve from C5 to C7), teres major (thoracodorsal nerves from C5 to C7).

• Arm, depression and lateral rotation. Infraspinatus (suprascapular nerve from C5 to C6).

• Elbow, flexion. Biceps brachii, brachialis (musculocutaneous nerve from C5 to C6).

• Elbow, extension. Triceps brachii (radial nerve from C7 to T1).

• Elbow, supination. Biceps brachii (musculocutaneous nerve from C5 to C6), brachioradialis (radial nerve from C5 to C6).

• Elbow, supination and elbow flexion. Brachioradialis (radial nerve from C5 to C6).

• Elbow, pronation. Pronator teres (median nerve from C6 to C7).

• Wrist, extension and adduction. Extensor carpi ulnaris (radial nerve from C7 to C8).

• Wrist, extension and abduction of hand. Extensor carpi radialis longus (radial nerve from C6 to C7).

• Wrist, extension of the hand. Extensor digitorum communis (radial nerve from C7 to C8).

• Wrist, flexion and abduction. Flexor carpi radialis (median nerve from C7 to C8).

• Wrist, flexion and adduction. Flexor carpi ulnaris (ulnar nerve from C7 to C8).

• Thumb, adduction and opposition. Adductor pollicis longus (ulnar nerve C8 to T1).

• Thumb, abduction and extension. Abductor pollicis longus and brevis (median and radial [and posterior interosseous nerves] from C7 to C8).

• Thumb, extension of distal phalanx. Extensor pollicis longus (radial nerve from C7 to C8).

• Thumb, extension of proximal phalanx. Extensor pollicis brevis (radial nerve from C7 to C8).

• Thumb, flexion of distal phalanx. Flexor pollicis longus (median nerve from C7 to T1).

• Thumb, flexion of proximal phalanx. Flexor pollicis longus and brevis (median nerve from C7 to T1).

• Thumb, flexion and opposition. Opponens pollicis (median nerve from C8 to T1).

• Fingers, flexion and adduction of little finger. Opponens digiti minimi (ulnar nerve from C8 to T1).

• Fingers, adduction of four fingers. Palmar interossei (ulnar nerve from C8 to T1).

• Fingers, abduction of four fingers. Dorsal interossei (ulnar nerve from C8 to T1).

• Fingers, extension of hand. Extensor digitorum communis (radial nerve from C7 to C8).

• Fingers, flexion of hand. Palmar interossei (interosseous nerves from C7 to T1), lumbricales (ulnar and median nerves from C7 to T1).

• Fingers, extension of interphalangeal joints. Interossei palmaris and lumbricales (interosseous nerve; median and ulnar nerves from C7 to T1).

• Fingers, flexion of the distal phalanges. Flexor digitorum profundus (median and ulnar nerves from C7 to T1).

• Fingers, flexion of middle phalanges. Flexor digitorum sublimis (median nerve from C7 to T1).

• Abdomen, compression with flexion of trunk. Rectus abdominis (lower thoracic nerves from T6 to L1).

• Abdomen, flexion of abdominal wall obliquely. Obliquus abdominis externus (lower thoracic nerves from T6 to L1).

• Hip, flexion. Iliacus (femoral nerve), psoas (L2 to L3), sartorius (femoral nerve from L2 to L3).

• Hip, extension. Gluteus maximus (inferior gluteal nerve from L4 or S2), adductor magnus (sciatic nerve and obturator nerve from L5 to S2).

• Hip, abduction. Gluteus medius (superior gluteal nerve from L4 to S1), gluteus maximus (inferior gluteal nerve from L4 to S2).

• Hip, adduction. Adductor magnus (sciatic and obturator nerves from L5 to S2).

• Hip, outward rotation. Gluteus maximus (inferior gluteal nerve from L4 to S2), obturator internus (branches from S1 to S3).

• Hip, inward rotation. Psoas (branches from L2 to L3).

• Knee, flexion. Biceps femoris, semitendinosus, semimembranosus, gastrocnemius (all through sciatic nerve from L5 to S2).

• Knee, extension. Quadriceps femoris (femoral nerve from L2 to L4).

• Ankle, plantar flexion. Gastrocnemius and soleus (tibial nerve from L5 to S2).

• Ankle, dorsiflexion. Anterior tibial (deep peroneal nerve from L4 to S1).

• Ankle, inversion. Posterior tibial (tibial nerve from L5 to S1).

• Ankle, eversion. Peroneus longus (superficial peroneal nerve from L4 to S1).

• Great toe, dorsiflexion. Extensor hallucis longus and brevis (superficial peroneal nerve from L4 to S1).

General Symptoms

Headache

The head contains many pain-sensitive structures, most innervated by the trigeminal nerve (CN V). Mechanisms of headache include inflammation, infection, arterial dilation, hemorrhage, changes of pressure within closed spaces, expanding mass lesions producing traction or compression of structures, trauma, tissue ischemia, and tissue destruction. The common extracranial cause of headache is sustained contraction of the head, neck, and shoulders muscles. Headache refers to more than momentarily pain in the cranial vault, orbits or nape of the neck; pain elsewhere in the face is not included. An urgent search for serious pathology is required if a severe headache is unlike any experienced in the past [Steiner TJ, Fontebasso M. Headache. BMJ. 2002;325:881–886]. CLINICAL OCCURRENCE: Congenital: Arteriovenous malformations, hydrocephalus; Endocrine: Pheochromocytoma; Idiopathic: Idiopathic intracranial hypertension; Inflammatory/Immune: Giant cell arteritis, sarcoidosis; Infectious: Meningitis, encephalitis, rickettsial infections, sinusitis, otitis, mastoiditis, non-CNS viral infections (e.g., influenza, cytomegalovirus, varicella), parasites (e.g., malaria, neurocysticercosis), protozoa (e.g., toxoplasmosis); Metabolic/Toxic: Analgesic rebound headache, hypoxia, hypercapnia, hypoglycemia, alcohol and illicit drug withdrawal, carbon monoxide poisoning, caffeine abstinence; Mechanical/Trauma: Accelerated and malignant hypertension, trauma (concussion), muscle tension, TMJ disease, increased intracranial pressure, glaucoma, decreased intracranial pressure (CSF leak); Neoplastic: Primary and metastatic brain tumors; Neurologic: Migraine, cluster headache, paroxysmal hemicrania, trigeminal neuralgia, occipital neuralgia; Psychosocial: Stress; Vascular migraine, intracranial aneurysm, hemorrhage (intracerebral, subdural, epidural, and subarachnoid), venous sinus thrombosis, stoke, cerebral vasculitis. For specific headache syndromes see Recurrent Headache Syndromes. Clinical Examination for Headache: History: Inquire carefully for the attributes of pain (PQRST); Provocative and Palliative Factors: Trauma, medications, substance abuse, position of the head and body, coughing, straining, emotional state, relief with massage, and resolution with sleep; Quality: Whether burning, aching, deep or superficial, lancinating, throbbing, or continuous; Region Involved and Radiation: Cranial, facial, orbital, unilateral, bilateral; Severity: Use the 1 to 10 scale; and Timing: when headaches began, frequency, time of day, duration, pattern of intensity. Inquire about family members with a headache history. Identify associated symptoms, for example, fever, stiff neck, nausea and vomiting, constipation or diarrhea, diuresis, rhinorrhea, visual disturbances (e.g., photophobia, scotomata, tearing, diplopia), cerebral symptoms (e.g., confusion, slurred speech, aura, paresthesias, anesthesias, motor paralysis, vertigo, mood, and sleep disturbances). Physical Examination: Inspect the skin and scalp for bulges and areas of erythema. With deep pressure palpate and percuss the bones of the cranium and face for tenderness and irregularities. Palpate the neck muscles and the upper borders of the trapezii for tenderness. Palpate the carotid and temporal arteries for pulsations and tenderness. Examine the eyes for pupil contour and response to light and near point, conjunctival injection or abnormal extraocular motion; use the confrontation test (Memory loss) to detect gross defects in the visual fields. Examine the fundus for choked disks and retinal hemorrhages. Auscultate the cranium for bruits. Perform a thorough neurologic examination with special attention to the CN and the deep tendon reflexes.

Memory loss

There are four components of memory that can be distinguished by function and location in the brain. Episodic memory records episodic events in the medial temporal and frontal cortex (cingulate gyrus). Semantic memory records names, general knowledge and information in the lateral temporal lobes. Procedural memory retains the ability to perform complex behaviors and tasks in the frontal lobes, basal ganglia and cerebellum. Working memory stores immediately useful information at which attention is directed in the frontal lobes, amygdala and parietal cortex. Information from working memory is either stored or deleted if not recalled or used. Patients often complain of forgetfulness, especially of people’s names. Paradoxically, it is rarely the patient who is concerned about memory loss who has a serious problem. Changes in behavior, failure to complete expected tasks, difficulty with instrumental activities of daily living, especially managing finances, are more likely to be clues to significant impairments in memory and cognition. Always formally screen for cognitive impairment if there is any concern. [Budson AE, Price BH. Memory dysfunction. N Eng J Med. 2005;352:692–699.]

Spells

The patient experiences one or more episodes of altered perception or behavior, usually of a duration measured in seconds or minutes. When multiple, they are usually described as stereotypic. The spell may have only subjective symptoms, or be associated with behavioral changes observed by others. The patient may be aware throughout the spell or be amnestic for the episode. When accompanied by changes in consciousness, behaviors or motor events, the reports of observers are often key to making the diagnosis. Inquire about triggering events or sensations, associated symptoms and signs (such as loss of muscle tone with falling, injury or incontinence), the duration of the spells and the patient’s responsiveness during and after the spell. Spells generally indicate a primary or secondary brain event. CLINICAL OCCURRENCE: Seizures, especially complex partial and absence seizures; transient ischemic events; stroke; nonconvulsive seizures; tics; conversion disorder; panic attacks; hyperventilation; narcolepsy; delirium; drug toxicity or intoxication.

Insomnia

Disorders of sleep are common, especially in shift workers and following long distance air travel. A careful history of the onset and pattern of disrupted sleep with close attention to sleep hygiene will often disclose the sources of sleep disruption. Several different patterns are recognized and should be distinguished: initial insomnia is the inability to get to sleep at the usual time; terminal insomnia results from early awakening and specifically produces deficits in rapid eye movement sleep. CLINICAL OCCURRENCE: Poor sleep hygiene, medications, illicit drug and alcohol use, depression, anxiety disorder, panic disorder, obstructive sleep apnea and hypomania or mania.

Loss of balance and falling

Maintaining balance requires normal proprioceptive sensory nerves and tracts, vestibular system, motor tracts and nerves, muscles, cerebellum, and basal ganglia. Major abnormalities in any one of these pathways can produce falls; more commonly, there are less severe impairments in several systems. Falls are a common problem, especially at advanced age. Many patients will not volunteer information about falls; they must be asked. When proprioceptive function is impaired, patients compensate with their eyes to locate themselves in space; visual impairment (including use of bi- and trifocal lenses) is a frequent contributor to falls. Skeletal abnormalities, especially of the joints, are a common precipitant. Decreased mentation and reaction times because of drugs (e.g., benzodiazepines, anticholinergics) or aging frequently contribute to a risk of falling. A complete neurologic examination is required to identify all contributing abnormalities. Fall prevention is a major focus of the geriatric assessment. Most falls take place during standing and transferring and are caused by loss of control of the center of mass rather than poor base support [Robinovitch SN, Feldman F, Yang Y, et al. Video capture of the circumstances of falls in elderly people residing in long-term care: an observational study. Lancet. 2013;381:47–54]. The major risk for future falls is a history of previous falls [Ganz DA, Bao Y, Shekelle PG, Rubenstein LZ. Will my patient fall? JAMA. 2007;297:77–86].

Cranial Nerve Symptoms

Visual loss

See Chapter 7.

Absent or abnormal taste and smell—ageusia, dysgeusia, anosmia

See Chapter 7.

Ringing in the ears—tinnitus

See Chapter 7.

Hearing loss

See Chapter 7.

Vertigo

See Chapter 7.

Double vision—diplopia

Perception of two visual images results from abnormalities of refraction or, less commonly, nonconjugative gaze. A careful history should determine the pattern of the symptom (e.g., vertical or horizontal), precipitating activities, the field of vision where the diplopia is apparent, and the position of the head or gaze that relieves the diplopia. If the patient reports monocular diplopia or diplopia when one eye is covered, the cause is nearly always refractive. Binocular diplopia results from impairment of the CN III, IV, and/or VI, damage to or weakness of the extraocular muscles, or displacement of the globe. Careful physical examination should be able to differentiate between these causes. Important diagnostic considerations are myasthenia gravis, Graves ophthalmopathy, and ophthalmoplegias.

Difficulty swallowing—dysphagia

See Chapter 7.

Difficulty speaking—dysarthria

See Dysarthria and dyslalia—articulation.

Difficulty speaking—aphasia

See Aphasia.

Pain in the face: trigeminal neuralgia/tic douloureux

Compression of CN V by an artery as it exits the brainstem is a common cause. A nonpainful stimulus provokes a paroxysm of “hot” lancinating pain, always unilateral, and initially limited to one division of the trigeminal nerve (CN V). The intense pain causes grimacing, hence the French term tic. Each patient has a unique, adequate stimulus in the trigger area: a light touch, chewing, sneezing, a draft, or a tickling of the skin. The maxillary division is most commonly involved with pain in the maxilla, upper teeth and lip and lower eyelid. Uncommonly, the mandibular division is involved with pain in the lower teeth and lip, the oral portion of the tongue and the external acoustic meatus. The ophthalmic branch is rarely affected. There are no motor or sensory changes. DDX: The initial stage of herpes zoster may suggest tic douloureux.

Asymmetrical face or smile

See Facial Nerve Signs.

Hoarseness

See Chapter 7.

Motor Symptoms

Weakness

See Hoarseness. Weakness may arise from lesions in the brain, spinal cord, peripheral nerves, motor endplate, or muscle. Either primary neuromuscular disease or generalized metabolic abnormalities can be the cause. Weakness is a common complaint that requires a complete evaluation. A careful history is required to identify the specific activities that are impaired. Difficulty with rising from a chair or climbing stairs suggests proximal muscle weakness, whereas difficulty writing, opening jars and doors, and catching the toes while walking suggest distal weakness. Global weakness can be seen with generalized muscle diseases, myasthenia gravis, and polyneuropathies (e.g., Guillain–Barré syndrome). During the physical examination observe for fasciculations, assess muscle mass, tone, and strength, and evaluate the reflexes. Hysterical weakness is not rare and malingering is perhaps more common; these diagnoses can only be made after organic disease is excluded by a thorough evaluation.

Acute episodic weakness—cataplexy

Episodic loss of motor and postural control is precipitated by laughter or strong emotions. There is momentary loss of voluntary motor power including speech, without loss of consciousness or postural tone. Cataplexy is seen in patients with narcolepsy.

Muscle pain—myalgia

See also Chapter 13. This is a common, but nonspecific finding. Generalized myalgias, especially in the back and proximal limb muscles frequently accompany febrile illness of any cause. Severe myalgias are common in several infectious diseases (e.g., Lyme disease, trichinosis, and dengue); other elements of the history are of more use than the presence of myalgia in making the specific diagnosis. Drugs (e.g., statins) also cause myalgias so a complete medication and herbal therapy history is mandatory. In persons older than 50, abrupt onset of myalgias in the proximal muscles (shoulders > pelvic girdle) suggests polymyalgia rheumatica.

Muscle stiffness

Overuse of skeletal muscle induces a damage–repair cycle that is felt by the patient as pain and stiffness. Underuse leads to muscle wasting, which may be accompanied by stiffness. The unconditioned patient often complains of sore, stiff muscles 1 to 2 days following unaccustomed exercise (weekend athlete syndrome). Examination shows no abnormalities other than tenderness and occasionally mild spasm in the affected muscles. Patients with inherited disorders of muscle metabolism or electrolyte disorders can develop severe myonecrosis with exercise. DDX: Abrupt onset of proximal muscles stiffness in a person over 50 without a clear-cut precipitating event suggests polymyalgia rheumatica. Generalized cramps with tetany are seen with hypocalcemia. Bradykinesia and increased muscle tone seen in Parkinson syndromes is often describe by the patient as stiffness. Rare causes are stiff person syndrome, myotonia, and hypocalcemia.

Twitches and tics

See Tics.

Irresistible leg movements—restless legs syndrome

See Restless legs syndrome.

Muscle spasm—cramps, dystonias

See Muscle stiffness.

Posture, Balance, and Coordination Symptoms

Loss of balance—falling

See Muscle stiffness.

Difficulty walking

See Dyssynergia and dysmetria.

Vertigo

See Chapter 7.

Tremors

See Tremors.

Sensory Symptoms

Altered sensation—tingling and numbness, paresthesias

Tingling and numbness of a body part indicate impairment of the normal sensory modalities of pressure, pain, and/or touch. Numbness implies neural damage and tingling stimulation of the nervous system. The symptom pattern gives a good indication of the anatomic level of the nerve injury: symptoms on one side of the entire body indicate a problem in the thalamus or cortex; loss on one side of the body below a specific level suggests spinal cord injury; symptoms in a peripheral nerve distribution implies injury to that nerve; and symmetrical distal paresthesia (stocking-glove distribution) suggests a generalized sensory (with or without motor) axonal neuropathy. Test for the specific modalities of sensation are required. Unilateral loss of touch and position sensation and contralateral loss of temperature and pain sensation indicate a unilateral lesion of the spinal cord ipsilateral to the loss of touch and position.

Pain with nonpainful stimuli—allodynia

See Allodynia.

Cranial Nerve Signs

The signs of CN dysfunction can be mimicked by non-neurologic end-organ diseases that must be considered during the head and neck examination; these signs are discussed fully in Chapter 7. Once end-organ disease is excluded, the challenge is to decide whether the neurologic lesion is central (brain) or peripheral (nerve). The following is a brief list of some specific cranial nerve signs.

Anosmia—Olfactory Nerve (CN I)

Lesions of CN I, often shearing of the nerve ending passing through the cribriform plate, or nasal obstruction produce loss of smell. Anosmia is invariably accompanied by a perceived change in the taste of food, which seems bland and unpalatable. The most common identified cause is closed head trauma.

Visual Field Signs

Monocular field defects—optic nerve or retina

Monocular visual field loss can occur from disease isolated to that eye. This would include disease of the retina or optic nerve. The optic nerve may be damaged to variable degrees from ischemia (giant cell arteritis, Anterior Ischemic Optic Neuropathy (AION), increased intraocular pressure (glaucoma), demyelinating disease (optic neuritis), trauma, and increased intracranial pressure. Destructive lesions of the retina also result in monocular field defects. Retinal ischemia from emboli, arteritis, or stenosis of the ipsilateral internal carotid artery may produce transient monocular blindness (amaurosis fugax). Retinal ischemia also results from ophthalmic artery or vein occlusion.

Bilateral visual field defects—hemianopsia (hemianopia)

Hemianopsia means that half of a visual field is not perceived. By definition, hemianopsia involves nerves projecting from both eyes, thus it must be caused by a lesion in the optic chiasm, the optic tracts, or the brain. The optic nerves carry all the nerve fibers from the ipsilateral retina. At the optic chiasm the fibers from the nasal retinas cross the midline (decussate) joining the fibers of the lateral retina from the opposite side to form the optic tracts. The right optic tract carries all fibers to the right side of the brain, projecting the left visual field (Fig. 14-20). The left side of the brain receives the right nasal and left temporal retinal fibers, projecting the right visual field of each eye.

Homonymous hemianopsia

The same side of each field contains a defect (Fig. 14-21A). A left homonymous hemianopsia can be caused by a lesion in the right optic tract or the right side of the brain. With a tract lesion, the pupillary reflex is lost if light is only projected from the blind hemifield; the pupil reacts when the lesion is posterior to the geniculate body in the optic radiations or occipital lobe. Transient homonymous hemianopsia may occur with migraine.

Crossed hemianopsia

Signals from both temporal or both nasal retinae are blocked, so the defect is bitemporal or binasal. A lesion of the decussating fibers in the chiasm causes bitemporal hemianopsia (Fig. 14-21B) by injuring the fibers from both nasal retinae, commonly a pituitary macroadenoma. Binasal hemianopsia is uncommon because it requires injury to both lateral halves of the optic nerves or tracts. When only a quadrant of each field is lost, it is termed quadrantanopsia.

Eye movement signs

Abnormalities of eye movements may be caused by either primary disease of the extraocular muscles, or by disease of the CNS and cranial nerves. For the nonspecialist the ability to distinguish neurologic from primary muscle disease is most critical. Therefore, these signs are discussed with the neurologic examination.

Nystagmus

One or both eyes cannot maintain fixation so the eyes drift slowly to one side returning back to the original position by a quick correcting movement. This is the normal eye movement to maintain fixation when the head is in motion. It can result from damage to the labyrinth, its cerebellar connections, or the cerebellum; there is instability when the patient stands with eyes open. Nystagmus is named after the direction of the quick component. It may be horizontal, vertical, rotatory, oblique, or mixed. When both eyes participate, the nystagmus is associated; movement of one eye only is dissociated. Fewer than 40 jerks per minute is “slow”; more than 100 jerks per minute is “fast.” Amplitudes <1 mm are fine; amplitudes >3 mm are coarse. DDX: There are several varieties of nystagmus. Ocular instabilities resembling nystagmus include ocular flutter, opsoclonus, and ocular bobbing.

• Congenital nystagmus is characterized by unsystematic wandering movements, with various frequencies and amplitudes.

• End-position nystagmus occurs only with fixation far to the side, so it is always in the direction of fixation (Fig. 14-22A).

• Labyrinthine end-position nystagmus usually occurs in disease of the semicircular canals; it is horizontal-rotatory and is initiated by fixation in the end position, but it persists for some time after the primary position has been resumed.

• Fixation nystagmus occurs in many normal persons when they are required to fix to one side or the other; it is horizontal or horizontal-rotatory, moderate to coarse.

• Muscle-paretic nystagmus presents as a dissociated movement of an eye with a paretic muscle when visual fixation is directed in the direction of action of the paretic muscle and the muscle attempts to maintain fixation.

• Gaze-paretic nystagmus appears in paralysis of conjugate movements. Both eyes show more nystagmus to one end position than to the other.

• Primary position nystagmus occurs with fixation in the primary position or at a point away from the direction of the quick component (Fig. 14-22B).

• Peripheral labyrinthine nystagmus is horizontal-rotatory, with medium frequency and amplitude, commonly seen in Ménière syndrome, benign paroxysmal positional vertigo, labyrinthitis, perilymphatic or labyrinthine fistula, and vestibular neuritis.

• Central nystagmus may be horizontal, rotatory, vertical, or mixed, usually in the direction of the diseased side. Commonly, it is found in multiple sclerosis, encephalitis, brain tumors, and transient or permanent vascular insufficiency states involving the vestibular nuclei or the medial longitudinal fasciculus.

• Vertical nystagmus usually indicates a lesion in the midbrain.

• Three types of nystagmus identify more localized lesions.

Convergence–retraction nystagmus occurs in the dorsal midbrain syndrome with lid retraction (Collier sign), limited up-gaze and light-near dissociation.

Seesaw nystagmus is found in parasellar lesions, and is characterized by rising and intorting of one eye whereas the other falls and extorts.

Downbeat nystagmus typically signifies lesions at the foramen magnum such as the Arnold–Chiari malformation, but may be seen with other disorders, including magnesium depletion, Wernicke encephalopathy and lithium intoxication.

Saccadic intrusions

Saccadic movements are rapid start-stop movements as opposed to the normal smooth pursuit movements when the eyes are fixed on a moving object. Voluntary eye movements are saccadic; you cannot move your eyes smoothly without fixing on a moving object. When saccadic eye movements occur inappropriately they suggest cerebellar disease. The quick component of nystagmus is a saccadic movement.

Ocular flutter

This is the arrhythmic and rapid movement of the eyes horizontally. When both horizontal and vertical components exist, it is termed opsoclonus. These conditions are associated with vascular, immune, neoplastic and paraneoplastic processes.

Ocular bobbing

This is the intermittent, conjugate, rapid, downward movement of the eyes followed by a slow return to primary position and is often seen in comatose patients with pontine lesions.

Abnormalities of Gaze

Oculomotor (CN III), trochlear (CN IV), and/or abducens (CN VI) nerve

See Figure 14-23. Unilateral complete paralysis is usually caused by direct pressure from tumor, aneurysm, or herniating brain. Less common are cavernous sinus thrombosis and granulomatous process at the base of the brain, for example, tuberculous meningitis and Tolosa–Hunt syndrome. Transient pupillary-sparing oculomotor and abducens nerve palsies may complicate diabetes mellitus.

Comitant strabismus (nonparalytic heterophoria)—constant squint angle

The muscles are normal; the disorder probably results from abnormal innervation in the cranial nerve nuclei because the squint angle disappears during general anesthesia. The word comitant, when applied to strabismus, indicates that the angle between the two optic axes, the squint angle, remains constant in all positions assumed by the globes, no matter which eye fixates. Neither eye has limited motion (Fig. 14-23). Because comitant strabismus occurs in the very young, children learn to suppress the image from one eye and do not have diplopia. In most cases, the optic axes converge, which is termed comitant convergent strabismus or esotropia. When hypermetropia causes excessive convergence, the condition is called accommodative squint. Occasionally the optic axes diverge, which is termed comitant divergent strabismus or exotropia.

Failure of convergence

A lesion in the frontopontine pathway is responsible. All movements are normal except convergence (Fig. 14-24E). Normal abduction of both globes to the right and left indicates that the medial recti are normal.

Varying squint angle—noncomitant strabismus (paralytic heterotropia)

This is caused by paralysis of one or more eye muscles: ophthalmoplegia. The squint angle changes with the direction of fixation. As opposed to comitant strabismus, the motions of the paralyzed eye are limited. The head is moved to limit the action of the paralyzed muscle to avoid diplopia. The squint angle is greatest when the unaffected eye is fixed on the visual field requiring the action of the paralyzed muscle, secondary deviation. When paralysis is acquired during maturity, diplopia occurs at the onset, frequently accompanied by vertigo.

To avoid confusion, only paralyses of the right eye are used as examples. In the figures, only the deficient eye movements are illustrated; all others are normal.

Right lateral rectus paralysis

In the primary position, the optic axes may be parallel, or the right eye may converge slightly (Fig. 14-23B). The right eye cannot move laterally. The lateral rectus muscles are the most frequent site of isolated paralysis. The abducens nerve (CN VI) may be damaged by ischemia, inflammation or in infectious diseases, periostitis of the orbit, fracture of the petrous portion of the temporal bone, aneurysm of the carotid artery within the cavernous sinus, and lesions of the posterior pons near the midline.

Right medial rectus paralysis

In the primary position, the right eye deviates laterally; it cannot move medially (Fig. 14-23C). The head is turned to the left to avoid diplopia.

Right superior rectus paralysis

In the primary position, the right eye deviates downward; it cannot move upward to the right (Fig. 14-23D). The squint angle and the diplopia increase with fixation of the left eye upward to the right.

Right inferior rectus paralysis

In the primary position, the right eye deviates upward; it cannot move down to the right (Fig. 14-23E). With the left eye fixed downward and to the right, the squint angle and the degree of diplopia increase.

Right superior oblique paralysis

In the primary position, the right eye deviates upward; movement is limited down and to the left (Fig. 14-24A). The squint angle is increased when the left eye is fixed downward and to the left. Most characteristic is the tilt of the head toward the left shoulder to compensate for the pronounced extorsion (ocular torticollis). This position results in the normal intorsion of the left eye correcting the torsional diplopia. If the head is tilted to the right side, the right eye rotates upward.

Right inferior oblique paralysis

In the primary position, the right eye deviates downward; its movement is limited upward and to the left (Fig. 14-24B). The squint angle increases when the left eye is fixed upward to the left.

Paralysis of two or more ocular muscles

Only the oculomotor nerve (CN III) supplies more than a single muscle, so partial ophthalmoplegia only involves CN III. Unilateral total ophthalmoplegia is caused by involvement of all the nerves in the superior orbital fissure or the cavernous sinus; a bilateral lesion could result only from a focus in the base of the brain.

Varying squint angle—complete right oculomotor (CN III) nerve paralysis

This produces paralysis of the levator, the superior, medial, and inferior recti, and the inferior oblique muscles and the pupillary sphincter (Fig. 14-24B). Only the superior oblique and the lateral rectus muscles are functioning. In the primary position, the right eye is deviated downward and outward to the right. Motion to the left and upward is absent. The squint angle and the degree of diplopia are increased when the left eye is fixed to the left. Ptosis is present from levator paralysis. The most frequent causes are an aneurysm in the circle of Willis and acute diabetic neuropathy; the latter usually spares the pupil.

Internuclear ophthalmoplegia

Internuclear ophthalmoplegia is caused by lesions of the medial longitudinal fasciculus interconnecting the nuclei of CN III, IV, and VI to coordinate conjugate eye movements. There is failure of adduction in horizontal lateral gaze, but convergence is normal. Common causes are multiple sclerosis or stroke.

Conjugate failure of lateral gaze

A disturbance in the frontopontine pathway is the cause (Fig. 14-24D). When the lesion is on the right, there is constant conjugate deviation to the right; the patient turns the head to the left to fixate in front. The optic axes are parallel in all positions, so there is no diplopia. Neither eye can move to the left of the midline. In partial failure of lateral gaze the patient can will the gaze to the left, but cannot fix it, so there is bilateral nystagmus to the left. DDX: This is distinguished from combined paralysis of the left lateral rectus and the right medial rectus by retention of convergence.

Conjugate failure of vertical gaze

This is a supranuclear disorder thought to be in the rostral midbrain. The patient is unable to gaze upward as the eyes cannot move above the horizontal so the head tilts backward. There is no diplopia. When failure is incomplete, there is slight upward movement with upward nystagmus. Rarely, upward failure is combined with downward failure, or failure of downward gaze may be present alone. DDX: Bilateral paralyses of the superior recti and the inferior obliques (innervated by CN III) produce similar findings, but vertical gaze palsy is distinguished by retention of the normal Bell phenomenon: reflex elevation of the globes when the lids close. This reflex is mediated by fibers between the nuclei of CN III and CN VII in the medial longitudinal fasciculus; CN III supplies the superior rectus and the inferior oblique, CN VII serves the orbicularis. Persistence of the reflex proves the intactness of both nuclei, so the lesion must be supranuclear.

Failure of convergence

A lesion in the frontopontine pathway is responsible. All movements are normal except convergence (Fig. 14-24E). Normal abduction of both globes to the right and left proves the medial recti to be normal

Pupil Signs

Normal pupil reaction

The sphincter contracts the pupil after parasympathetic stimulation; the dilator widens the pupil with sympathetic stimuli. The sphincter pupillae is a circular muscle embedded in the iris near the pupillary margin. It is innervated by parasympathetic fibers from the Edinger–Westphal nucleus near the oculomotor nerve (CN III) nucleus (Fig. 14-25). The fibers enter the orbit in the third nerve and accompany its motor branch to the inferior oblique muscle, whence the parasympathetic fibers synapse in the ciliary ganglion; from there, other fibers enter the eye through the short ciliary nerves. The dilator pupillae is arranged radially in the peripheral two-thirds of the iris. It receives sympathetic fibers arising in the cortex, descending to the hypothalamus and ciliospinal center; postsynaptic fibers go to the cervical sympathetic chain and ascend to the superior cervical ganglion. They synapse with third-order neurons that run to the carotid plexus, and then to the first division of the trigeminal nerve (CN V) into the eye. Pupil size fluctuates related to changes in tone of these muscles. Exaggerated wavering is termed hippus, or physiologic pupillary unrest; it is of little clinical significance. Mydriasis is dilatation; miosis is pupillary constriction. Bright light causes constriction, accompanied by a consensual reaction in the unexposed eye; the pupils remain equal in size. In older persons, the pupils may react sluggishly to light; the reaction is hastened after several stimulations. Near point miosis, associated with lens accommodation, occurs when the eye is fixed on a near object. The pupils of patients with Cheyne–Stokes respirations may dilate during the phase of hyperventilation and constrict with apnea.

Unequal pupils—anisocoria

Unequal pupils occur from either constriction or dilation of one pupil. Anisocoria is often unimportant, and beware the artificial eye. To determine whether one pupil is too small or the other too large, measure them in bright and dim light. If one pupil cannot contract the discrepancy is exaggerated in bright light. If one pupil cannot dilate, the difference is greater in darkness. Physiologic anisocoria is a normal finding in 20% of patients; it manifests as a constant difference in pupillary diameter in light and dark. CLINICAL OCCURRENCE: Miosis of one pupil with a large size disparity suggests damage to the sympathetic nerves (Horner Syndrome), iris sphincter inflammation (iritis), or use of a miotic drug (e.g., pilocarpine). Dilatation of one pupil can result from parasympathetic nerve damage (CN III paralysis from posterior communicating artery aneurysm), iris ischemia from acute, severe increase in intraocular pressure (angle closure glaucoma), damage to the ciliary ganglion (Adie tonic pupil), or a mydriatic drug (e.g., atropine), An artificial eye will be painted with a pupil midway between constricted and dilated so will also manifest anisocoria.

Relative afferent pupillary defect (RAPD, Marcus–Gunn pupil)

There is an asymmetric decrease in light detection by the retina or in signal transmission through the optic nerve and tract to the geniculate ganglia and Edinger–Westphal nuclei. Both pupils constrict less when light is directed into the pupil of the affected eye than when directed into the unaffected eye using the swinging light test (Examination of the iris, pupils, and lens).

Argyll Robertson pupil

There is no agreement on the site of the lesion in the nervous system [Aziz TA, Holman RP. The Argyll Robertson pupil. Am J Med. 2010;123:120–121]. The classic signs are severely miotic pupils with weak or absent contraction to light that do not improve with dark adaptation, but have normal or exaggerated contraction to near point (“accommodation”). The pupils may be irregular and unequal in size. The fully developed Argyll Robertson pupil is almost pathognomonic of tabes dorsalis or taboparesis.

Tonic pupil (Adie pupil)

Adie tonic pupil is in the differential diagnosis of anisocoria because of a dilated pupil. The reaction to light and near focus are present but extremely sluggish and have a prolonged latent period prior to onset of constriction. The response to light may be absent, with a full but tonic response to near point focus. Classically there are sectoral or vermiform movements of both the pupillary border and the related sector of iris stroma, demonstrating the partial parasympathetic denervation of the pupil. It is usually unilateral, but may be bilateral. DDX: Tonic pupil is most frequently encountered in young women with normal-sized pupils, in contrast to the requisite miosis in the Argyll Robertson pupil; whatever the degree of reaction in the Argyll Robertson pupil, its reaction is prompt.

Unreactive pupil—internal ophthalmoplegia

The pupil lacks the ability to constrict from either light or accommodation. It is generally dilated, never miotic. CLINICAL OCCURRENCE: Topical mydriatics are most common; less-common causes are syphilitic meningitis, vasculitis, viral encephalitis, diphtheria or tetanus toxin, lead poisoning, midbrain lesions, bilateral CN III lesions, Adie pupils, iris dysfunction from trauma, and systemic anticholinergic medications (e.g., scopolamine patches, benztropine mesylate).

Unilateral miosis—Horner syndrome

This is caused by a lesion of the sympathetic pathway. In the complete syndrome it is accompanied by ptosis and anhydrosis on the affected side. See Horner syndrome.

Other Cranial Nerve Signs

Jaw weakness and spasm—CN V, trigeminal nerve

Jaw closure may be weak and/or asymmetric. The jaw jerk may be absent or hyperreflexic. Irritative lesions of the motor root may cause spasm or trismus.

Facial weakness and paralysis—CN VII, facial nerve

Because the LMN of the lids and forehead are innervated bilaterally by the UMN, UMN lesions do not affect the upper lid or forehead. The following are key observations to help localize the lesion and resulting functional impairments: (1) Face in repose: shallow nasolabial folds in both UMN and LMN; palpebral fissure widened in LMN; (2) Eyebrow elevation and forehead wrinkling is absent in LMN, but present in UMN; (3) Frowning: lowering of the eyebrow is absent in LMN, present in UMN; (4) Tight closing of an eye is absent in LMN, with an associated upturning of the unclosed eye (Bell phenomenon). The lids close normally in UMN. When the eyes are tightly closed, weakness of one upper lid can be detected by forcing the lids open with the thumb. Irritation of the cornea (keratitis) and conjunctivae (keratoconjunctivitis sicca) may occur as a result of inadequate lid closing; (5) Showing teeth: the lips do not retract fully in either UMN or LMN (Fig. 14-5C); (6) Whistling and puffing cheeks are absent or diminished in both UMN and LMN. Weakness can cause pocketing of food in the cheeks and difficulty with mastication; and (7) A natural smile: the lips and corners of the mouth do not fully elevate with LMN lesions. The paralysis is overcome by movements responding to emotion, so a symmetrical smile may occur in UMN disease. Abnormalities of taste will accompany LMN lesions. Facial spasm, clonic contractions of the facial muscles, may occur following partial denervation of the facial muscles. CLINICAL OCCURRENCE: The cause of peripheral facial nerve palsies is usually unproven. They occasionally occur in sarcoidosis, tumors of the temporal bone and cerebellopontine angle, poliomyelitis and post-polio syndrome, neoplasms, infectious polyneuritis (Guillain–Barré syndrome), Lyme disease, herpes simplex, AIDS, and syphilis. In the Ramsay–Hunt syndrome, varicella-zoster virus infects the geniculate ganglion of the sensory branch of the facial nerve to produce a facial palsy, loss of taste on the anterior two-thirds of the tongue, and pain and vesicles in the external auditory canal on the same side. Herpetic lesion in the ear canal is the clue to diagnosis. Idiopathic facial nerve paralysis is Bell palsy.

Abnormal corneal reflex—CN V and VII

The corneal reflex is a bilateral reflex testing the fifth and seventh CN on the side stimulated and the seventh consensually. With an afferent (CN V) lesion, the response from both sides will be depressed. With an ipsilateral efferent (CN VII) lesion, the direct reflex is lost, but the consensual is preserved.

Abnormal hearing—auditory nerve (CN VIII)

See Chronic suppurative otitis media.

Abnormal balance—auditory nerve (CN VIII)

See Loss of balance and falling.

Dysarthria—glossopharyngeal (CN IX) and/or vagus (CN X) nerve

Patients will have difficulty with articulation and the pharyngeal phase of swallowing. Examination shows poor and/or asymmetric elevation of the soft palate and uvula. Absence of elevation indicates bilateral paralysis. Unilateral injury causes deviation of the uvula toward the strong side (see Fig. 14-5D).

Dysphagia—glossopharyngeal (CN IX) and/or vagus (CN X) nerve

See Chapter 7. Laryngeal paralysis (CN X, recurrent laryngeal nerve) may cause coughing or reflux into the posterior nose when swallowing liquids.

Hoarseness—vagus nerve (CN X)

See Chapter 7. Hoarseness may indicate unilateral vocal cord paralysis, whereas dyspnea and inspiratory stridor are associated with bilateral involvement.

Weak head rotation and shoulder shrug—CN XI, accessory nerve

Sternocleidomastoid and trapezius weakness produce weak head rotation and shoulder shrug.

Tongue deviation and wasting—CN XII, hypoglossal nerve

The tongue protrudes by tensing the two lateral muscle bundles; paralysis of one bundle causes the tongue to deviate to the paralyzed side (see Fig. 7-49). With longstanding lesions, the two halves of the tongue are of unequal size because of muscle atrophy.

Motor Signs

Most abnormal movements result from normal muscles responding to abnormal uncoordinated neural control signals.

Weakness—muscle paralysis, paresis, and palsy

Paralysis is defined as complete loss and paresis as diminution of muscle power from abnormalities of the UMN, LMN, peripheral nerve, or muscle fibers. Palsy is a nonspecific descriptive term that indicates varying degrees of paralysis and/or paresis. Increased tone and uninhibited reflexes (spasticity) occur with UMN lesions, whereas LMN and peripheral nerve lesions result in flaccid paralysis and muscle wasting. Primary disease of muscle is associated with flaccid paralysis and variable changes in muscle bulk. It is essential to take a careful history to assess the onset of paralysis: acute, subacute, or chronic. Muscle wasting results from disuse; muscle atrophy from LMN denervation, indicated by fasciculations. CLINICAL OCCURRENCE: Congenital: Porphyria, muscular dystrophy, familial periodic paralysis, paramyotonia congenita, cerebral palsy; Endocrine: Hyperthyroidism; Idiopathic: Noninflammatory myopathies; Inflammatory/Immune: Guillain–Barré syndrome, chronic idiopathic demyelinating polyneuropathy, myasthenia gravis, polymyositis, dermatomyositis, multiple sclerosis (MS), vasculitis; Infectious: Poliomyelitis, post-polio syndrome, West Nile virus; Metabolic/Toxic: Electrolyte disturbances (high or low potassium, magnesium, calcium, low copper), drugs (muscle relaxants, anesthetics, aminoglycosides rarely), heavy metal poisoning, beriberi, anemia, pernicious anemia, amyloidosis; Mechanical/Trauma: Brain and spinal cord trauma, peripheral nerve trauma; Neoplastic: Epidural metastases; Neurologic: Polyneuropathy, transverse myelitis; Psychosocial: Hysteria, malingering; Vascular: Stroke, spinal cord infarction, subdural and epidural bleeding, vasculitis.

Muscle wasting

Loss of the trophic effect of motor nerves on muscle fibers results in the severe muscle wasting typical of LMN lesions. A lesser degree of wasting results from peripheral nerve injury and much less with UMN lesions. Wasting becomes apparent weeks to months following the nerve injury. Fasciculations are seen with LMN lesions, but are absent with UMN lesions. Generalized weakness and wasting accompanied by fasciculations, often most evident in the tongue and small muscles of the hands, along with UMN signs, suggest primary motor neuron disease, for example, amyotrophic lateral sclerosis. Segmental disease is characteristic of poliomyelitis, West Nile virus, and diseases of the spinal cord and nerve plexuses.

Decreased muscle tone—hypotonia

Decreased resting muscle tone occurs with LMN injury, such as poliomyelitis, a root syndrome, and peripheral neuropathy. It is also encountered in cerebellar and other central lesions.

Increased muscle tone—hypertonia

Extrapyramidal lesions, such as parkinsonism, produce increased resting muscle tone.

Cogwheel rigidity

On passive limb motion muscular resistance is felt as a series of stepwise relaxation–arrest cycles, rather than a smooth giving way. This is characteristic of Parkinsonism. It is disappears during sleep.

Myoclonus

A single, sudden jerk, or a short series, occurring succession, may be so powerful as to throw the patient to the floor. Unlike tremor, myoclonus may not disappear with sleep and is frequent at sleep onset. It is a common complication of chronic meperidine use and other metabolic encephalopathies.

Myotonia

The muscles continue in contraction after a voluntary or reflex action has ceased. Similarly, relaxation of a contraction induced by tapping the muscle belly with a reflex hammer is prolonged. After shaking hands, the fingers are slow to relax. When the fingers are flexed on the supinated palm, attempted extension is slow and difficult. Myotonia is typical of myotonia congenita and myotonic dystrophy [Nanayakkara PW, Hartdorff CM, Steovwer CD, Vermeulen RJ, de Visser M. A man with fever and a persistent handgrip. Lancet. 2003;362:1038].

Tetany

The threshold for muscular excitability is lowered such that involuntary sustained contractions occur, either painless or painful. Any cause of a low ionized serum calcium can result in tetany, including hypoparathyroidism, acute hyperventilation, and hypomagnesemia. The contracting muscles feel rigid and unyielding. Spasm may be preceded by numbness and tingling in the lips and limbs. Contractions of the hands and feet are collectively termed carpopedal spasm. In carpal spasm, the wrist is flexed and flexion at the metacarpophalangeal joints is combined with extension of the interphalangeal joints. The hyperextended fingers are also adducted to form a cone and the thumb is flexed on the palm. In latent tetany, carpal spasm may be induced by occluding the brachial artery for 3 minutes with an inflated sphygmomanometer cuff, the Trousseau sign. Tapping the facial nerve against the bone just anterior to the ear produces ipsilateral contraction of facial muscles, Chvostek sign. It is uniformly present in latent tetany but also occurs in some normal persons.

Fasciculation

Damage to the nerve supplying a muscle leads to visible fasciculation from spontaneous motor unit firing. Fibrillations are twitches of individual muscle fibers; they are invisible, but can be demonstrated by electromyography. Coarse twitches are often caused by exposure to cold, fatigue, or other conditions, and are not serious. Fasciculations are not powerful enough to move a joint or a part, so the muscle must be at rest for them to be seen. In the presence of muscle wasting or weakness, fasciculations are attributable to denervation of the muscle.

Reflex Signs

Clonus and spasticity

Normally, central inhibition of the spinal cord limits the stretch reflex to a single beat. Loss of inhibition allows the reflex to become self-perpetuating. Spasticity occurs with complete loss of cortical inhibition, leading to sustained contractions of opposing muscle groups, the flexors dominating in the arms, and the extensors in the back and legs. A hyperactive reflex may produce clonus, a rhythmic contraction of muscles initiated by stretching. During the acute stage after injury, as in spinal shock, stretch reflexes are absent. When a spastic limb is moved the resistance may suddenly cease, giving a clasp-knife effect. Long, continued spasticity results in muscle fibrosis and shortening, known as contracture. Clonus may be unsustained, just a few jerks, or sustained, persisting as long as stretch is applied. A pyramidal tract lesion almost invariably causes complete suppression of the superficial skin reflexes caudal to the level of the lesion.

Ankle clonus

With the patient’s knee flexed, grasp the foot and briskly dorsiflex it. Rhythmic contractions of the gastrocnemius and soleus cause the foot to alternate between dorsiflexion and plantar flexion (Fig. 14-12C).

Patellar clonus

With the patient supine and the relaxed lower limb extended, grasp the patella and push it quickly distal. The patella will jerk up and down from the rhythmic contractions of the quadriceps femoris.

Wrist clonus

Grasp the patient’s fingers and forcibly hyperextend the wrist. The wrist will alternate rhythmically between flexion and extension because of contraction of the wrist flexors.

Hoffmann sign—finger flexor reflex

This has the same significance as other muscle stretch reflexes. Hold the patient’s pronated hand in your hand, with fingers extended and relaxed. Support the patient’s extended middle finger by your right index finger held transversely under the distal interphalangeal joint crease (Fig. 14-26B). With your thumb, press the patient’s fingernail to flex the terminal digit. The abnormal reflex is flexion and adduction of the thumb. The other fingers may also flex. When the reflex is present bilaterally, it may be a normal variant.

Babinski sign

See Plantar Reflex. Babinski sign is a pathologic response to noxious stimuli in or spreading to the S1 dermatome resulting from loss of central inhibition on the spinal cord. Partial responses include only dorsiflexion of the great toe, failure of the small toes to abduct or fan, and fanning of small toes without great toe dorsiflexion. Complete and partial responses are all indicative of different degrees of pyramidal disease, so the details of response should be accurately recorded. Alternate methods of eliciting Babinski reflex have been described as eponymic signs. In the Oppenheim sign, great toe dorsiflexion is elicited with pressure applied by the thumb and index finger or knuckles to the anterior tibia. The pressure stroke should begin at the upper two-thirds of the bone and be continued to the ankle. In Chaddock sign, the stimulus is a scratch with a dull point. The path of stimulation should curve around the lateral malleolus of the ankle, then along the lateral aspect of the dorsum of the foot.

Primitive reflexes (release signs)

Each of these signs may indicate diffuse cerebral disease, but are sometimes present in normal individuals.

Grasp reflex

Though normal in infants, in adults it indicates a lesion of the premotor cortex. Place your index and middle fingers between the patient’s thumb and index finger, laying them across the patient’s palm. Gently pull them across the palm with a stroking motion. Grasping with the thumb and index finger is a positive response (Fig. 14-26A). The patient cannot release the fingers at will.

Palmomental reflex

Scratching or pricking the thenar eminence causes ipsilateral contraction of the muscles of the chin.

Snoutsuck reflexes

Scratching or gentle percussion of the upper lip may induce a puckering or sucking movement.

Spinal Automatisms

Spinal automatisms occur when the central inhibitions of reflexes are lost in severe disease of the spinal cord or brain.

Spinal reflex reactions

In extensive lesions of the cord or midbrain, painful stimulation of a limb may produce ipsilateral flexion of both upper and lower extremities, called ipsilateral mass flexion reflex, spinal withdrawal, or shortening reflex.

Mass reflex

A transverse lesion of the cord may produce flexion followed by extension of the limbs below the level of lesion. In complete transection, only flexion occurs, accompanied by contractions of the abdominal wall, incontinence of urine and feces, and autonomic responses, such as sweating, flushing, and pilomotor activity. This complex is termed mass reflex. Involuntary urination may be stimulated by stroking the skin on the thighs and abdomen, an automatic bladder. Priapism and seminal ejaculation may be induced by similar mechanisms. In the crossed extensor reflex, flexion of one limb may be associated with extension of its counterpart. In some cases, the extensor thrust reaction is encountered: pressure on the sole causes extension of the leg. When the leg is placed in flexion, scratching on the skin of the thigh induces leg extension. Painful stimulation of the arm or chest may cause abduction and outward rotation of the shoulder.

Signs of meningeal irritation

Irritation of the meninges by meningitis, subarachnoid hemorrhage, drugs, and increased intracranial pressure cause abnormal contraction of various muscle groups, which are identified on physical examination. Nuchal Rigidity: The patient cannot place the chin on the chest. Passive flexion of the neck is limited by involuntary muscle spasm, whereas passive extension and rotation are normal. Kernig Sign: With the patient supine, passively flex the hip to 90 degrees while the knee is flexed at about 90 degrees (Fig. 14-27A). With the hip kept in flexion, attempts to extend the knee produce pain in the hamstrings and resistance to further extension. Brudzinski Sign: With the patient supine and the limbs extended, passively flex the neck. Flexion of the hips is a positive Brudzinski sign (Fig. 14-27B).

Spinal rigidity

Spine movements are limited by erector spinae spasm. In extreme cases, the spinal muscles are in tetanic contraction, producing rigid hyperextension of the entire spine with the head forced backward and the trunk thrust forward; this is opisthotonos.

Cerebellar Signs

Ataxia

Disorders involving the cerebellum, proprioception, labyrinth, and vision can result in poorly coordinated movements. Uncoordinated movement or maintenance of posture is ataxia. If present lying down, it is static ataxia. If the ataxia is only evident on standing or moving, it is kinetic ataxia. Cerebellar ataxia is not ameliorated by visual orientation. Ataxia from posterior column disease involves disordered proprioception; it is partially compensated by a wide stance, and worsens when the eyes are closed. Proprioceptive ataxia may only appear when the eyes are closed, for example, Romberg sign.

Cerebellar ataxia

The gait is staggering, wavering, and lurching, and not visually compensated. With a lesion in the mid-cerebellum or vermis, instability is in all directions; when one lateral lobe is involved, staggering and falling are toward the affected side. The ataxia is partially compensated by a wide base. Ataxia secondary to vestibular disease may be similar.

Impaired proprioception

The lesion may be in peripheral sensory nerves (e.g., diabetes) or posterior column of the spinal cord (e.g., vitamin B₁₂ or copper deficiency, tabes dorsalis); in either case, proprioceptive impulses to the brain are defective. The gait and stance are facilitated by a wide stance. In walking, the feet are lifted too high and frequently are set down with excessive force. The eyes are used to compensate for loss of proprioception, so the ataxia is much greater with the eyes closed.

Apraxia

Apraxia is the inability to convert an idea into a skilled act. It is best tested by attempting previously learned skills. Perfect execution of skilled acts is eupraxia.

Dysdiadochokinesis

Loss of the ability to arrest one motor impulse and substitute its opposite, dysdiadochokinesia, is characteristic of cerebellar disease (see Testing for Diadochokinesia).

Dyssynergia and dysmetria

Failure to coordinate the contraction of synergistic muscle during a movement is dyssynergia. Inability to control the distance, power, and speed of a movement is dysmetria. Finger-to-Nose Test: In cerebellar disease, this action is attended by an action tremor. When the maneuver is performed with the eyes closed, the sense of position in the shoulder and elbow is tested. Heel-to-Shin Test: In cerebellar disease, the arc of the heel to the knee is jerky and wavering, the knee is frequently overshot, and the slide down the shin is accompanied by an action tremor. In posterior column disease, the heel may have difficulty finding the knee, and the ride down the shin weaves from side to side, or the heel may fall off altogether.

Romberg sign

Stable standing with the eyes closed requires normal labyrinthine function, position sense, cerebellar function, and strength. Persistent labyrinthine stimulation or loss of position sense leads to unsteadiness, elevation of the arms for balance or falling. With labyrinthine stimulation, the patient will fall in the same direction as the flow of endolymph. Inability to maintain balance with the eyes open suggests abnormalities of the labyrinth, cerebellum, or sight. Record the sign as Romberg present or absent.

Positive past pointing test

Deviation to the right or left of the target fingers, past pointing, indicates either labyrinthine stimulation or loss of positional sense. The flow of endolymph is in the same direction as the past pointing.

Gait Disorders

Foot drop—steppage gait

Paralysis of the ankle dorsiflexors causes the foot to slap down onto the floor. To compensate for the toe drop, the patient must raise the thigh higher, as if walking upstairs. Unilateral toe drop usually results from injury of the peroneal nerve. Bilateral paralysis may occur from polyneuropathies, poliomyelitis, lesions of the cauda equina, or peroneal atrophy in Charcot–Marie–Tooth disease.

Hemiplegic gait

The patient walks with the affected leg extended at the hip, knee, and ankle, and the foot inverted. The thigh may swing in a lateral arc (circumduction) or the patient may push the inverted foot along the floor.

Spastic gait, scissors gait

In paraparesis with adductor spasm, the knees are pulled together so the body must sway laterally away from the stepping limb to allow it to clear the floor. The feet may overstep each other laterally, alternately crossing across the line of travel with each step.

Parkinson gait—festinating gait

See Parkinson disease and parkinsonism. The trunk and neck are rigid and flexed. The arm swing is diminished or lost unilaterally or bilaterally. The steps are short and shuffling and become faster in an attempt to avoid falling forward (chasing the center of gravity: festination). Turns are slow and in-block, without turning of the head on the trunk or the trunk on the pelvis.

Magnetic gait

The stance is wide and the steps are short and shuffling. The feet are not lifted from the floor, as if held down by magnets. This indicates diffuse cerebral disease or multisystem damage.

Waddling gait—muscular dystrophy

The patient walks with a broad base. The thighs are thrown forward by twisting the pelvis to compensate for the weak quadriceps muscles. A similar gait is used by those with bilateral dislocations of the hips.

Gait ataxia and dementia

Ataxia of gait in patients without dementia is associated with a significantly increased risk for non-Alzheimer dementia during a follow-up of over 6 years [Verghese J, Lipton RB, Hall CB, Kuslansky G, Katz MJ, Buschke H. Abnormality of gait as a predictor of non-Alzheimer’s dementia. N Engl J Med. 2002;347:1761–1768].

Movement Disorders

Tremors

Coarse, poorly coordinated, contractions of opposing muscle groups are unable to maintain stable posture and/or smooth movement resulting in oscillating movements at one or more joints. The amplitude may be either fine or coarse, and the rate either rapid or slow. Movements may be rhythmic or irregular. All tremors disappear during sleep. Examine the affected part at rest with the muscles relaxed (repose), with maintenance of posture against gravity and with movement.

Essential tremor

This is an accentuation of the normal fine motor movements made to maintain posture. It is accentuated with increased adrenergic stimulation of muscle and may be a familial trait. The tremor is rapid and fine. It is absent is repose and accentuated by trying to maintain a posture [Pahwa R, Lyons KE. Essential tremor: differential diagnosis and current therapy. Am J Med. 2003;115:134–142; Louis ED. Essential tremor. N Engl J Med. 2001;345:887–891]. Everyone has this tremor, but usually at amplitude below visible detection. It is accentuated with anxiety and is characteristic of hyperthyroidism and alcohol withdrawal.

Parkinson tremor

See Parkinson Disease. The tremor is present at rest and diminished or absent with movement. It is slow and coarse, and often described as “pill-rolling” from the characteristic movements of the fingers and wrist. Parkinson disease tremor is asymmetric at onset [Utti RJ. Tremor: how to determine if the patient has Parkinson’s disease. Geriatrics. 1998;53:30–36].

Cerebellar tremor

Poor cerebellar coordination of muscle contraction associated with movement leads to limb oscillation, often accentuated with attempts at fine control. Action or intention tremor occurs in MS and cerebellar disease in which voluntary movements initiate and sustain a slow oscillation of wide amplitude.

Tics

Normal movements of muscle groups, such as grimacing, winking, or shoulder shrugging, are repeated at inappropriate times. The reaction is stereotyped for the individual. Tics may be acquired behavioral habits or a sign of organic disease, for example, Tourette syndrome. They may be abolished by diverting the patient’s attention and they disappear during sleep.

Dyskinesia

Dyskinesias are complex abnormalities of muscle movement. They are centrally mediated. Several characteristic patterns are recognized.

Chorea

Rapid, purposeless, jerky, asynchronous movements involve various parts of the body. Although some are spontaneous, many are initiated and all are accentuated by voluntary acts, as in extending the arms or walking. They commonly occur in both Sydenham and Huntington chorea; in the latter, the movements are coarser and more bizarre. They disappear with sleep.

Athetosis

Compared to chorea, athetosis is slower and writhing, resembling the actions of a worm or snake. The distal parts of the limb are more active than the proximal parts. Grimaces are more deliberate than in chorea. The grotesque athetoid hand is produced by flexion of some digits with others extended. They disappear with sleep. The mechanism is not understood, but the movements are frequently associated with diseases of the basal ganglia and levodopa therapy for Parkinson disease.

Hemiballismus

One side of the body is affected by sustained, violent, involuntary flinging movements of the limbs. These result from a lesion in the contralateral subthalamic nucleus of Luys, usually secondary to stroke. They disappear with sleep.

Asterixis

When the arms are held straight forward from the shoulders with the fingers and wrists extended and fingers spread, there is sudden loss of wrist and interphalangeal extensor tone. This loss and regaining of tone results in a flapping motion. The fingers deviate laterally and exhibit a fine tremor. A similar flap occurs at the ankle when the leg is elevated and the foot dorsiflexed. Ask the obtunded patient to squeeze two of the examiner’s fingers; asterixis is felt as an alternately clenching and unclenching grip. Asterixis occurs in any form of metabolic encephalopathy including liver failure, uremia, and hypercapnia.

Muscle cramps—dystonias

See Dystonia.

Loss of synkinesia

Synkinesias are involuntary motor patterns, more complex than reflexes, that normally accompany voluntary acts. Examples include swinging the arms while walking, facial movements of expression, and motions accompanying coughing and yawning. Frequently, these are lost in disease of the pyramidal tract or basal ganglia. For example, the patient with parkinsonism walks without swinging the arms. An early sign of corticospinal tract damage may be loss of synkinetic movements. Knowledge of normal and abnormal patterns of synkinesis can assist in the identification of the patient with factitious neurologic illness. The detailed testing of synkinesis is beyond the scope of this text. The reader should consult textbooks of neurologic diagnosis.

Sensory Signs

Loss of normal sensation can result from injury to either the peripheral or CNS. The distribution of the sensory loss, the modalities involved and the presence or absence of motor involvement are useful in distinguishing peripheral nerve from plexus, root, and central injury.

Allodynia

Allodynia indicates damage to the sensory pathways, usually in the dorsal root or spinal cord; it is not a sign of peripheral nerve injury. Allodynia (allo = differing from normal; dynia = pain) is the perception of pain with stimuli that are normally not painful such as light touch or vibration. Patients complain of pain with the touch of clothing or bedding and with weight bearing on the feet. Lightly touch and stroke the skin over the suspected area and apply a tuning fork to look for allodynia. Use a mildly uncomfortable stimulus like the sharp end of a broken tongue depressor to elicit hyperesthesia. DDX: Allodynia is commonly seen with post-herpetic neuralgia, diabetic radiculopathy, and complex regional pain syndrome.

Hyperalgesia

Stroke the skin lightly with a pin or, alternatively, gently lift a skin fold off the underlying tissue without squeezing it. The sensation is more intense, but not painful in areas of cutaneous hyperesthesia.

Analgesia and hypalgesia

Decreased or absent pain sensation indicates damage to the peripheral or central pain pathways. The distribution of the lost sensation (peripheral nerve, dermatome) will indicate the level of the lesion. Look for loss of other modalities, especially temperature and touch.

Hysterical anesthesia

Hysteria may be revealed by outlining the borders of an area of anesthesia stimulating from the center to the border in a zigzagging line and then in the opposite direction. Repeat after examining other areas. A disparity between successive tests supports this diagnosis.

Loss of pain and temperature sensation

Pain and temperature fibers cross near their entry into the cord. Disruption of the crossing fibers leads to loss of these modalities with preservation of other regional sensation. Ask the patient to distinguish between hot and cold. Temperature and pain discrimination is lost in syringomyelia whereas tactile sense is retained.

Tactile extinction

In parietal lobe disease, the patient may perceive touch accurately when the stimulus is applied to the right and left consecutively, but if stimulated simultaneously, the patient no longer perceives, or extinguishes, the affected side.

Loss of position and vibration sense

Damage to the posterior columns of the spinal cord results in impaired proprioception leading to abnormalities in stance and gait. Posterior column diseases include vitamin B₁₂ or copper deficiency and tabes dorsalis.

Loss of integrative function—astereognosis

Inability to recognize familiar objects by touch is astereognosis. Assuming the primary sensory modalities are intact, it is a sign of cortical disease, an inability to integrate the multiple inputs.

Autonomic Nervous System Signs

Temperature regulation

See Chapter 4. Some instances of hyperthermia occur from hypothalamus or high cervical cord lesions. Hypothermia is encountered in insulin shock and myxedema, although the role of the autonomic system in the latter condition is doubtful.

Perspiration

Localized areas of sweating may occur in syringomyelia, peripheral nerve injury, or neuropathy. Anhidrosis is a component of Horner syndrome, autonomic insufficiency (severe combined degeneration), and anticholinergic medications or poisoning. Increased perspiration can be seen with use of b-blockers.

Trophic disturbances

Loss of innervation leads to functional deficiencies of the sweat and oil glands of the skin. Combined with decreased sensation, the skin is more vulnerable to injury and infection. The skin becomes shiny, smooth, thin, and dry. Painless ulcers may develop over bony prominences of the feet in peripheral neuropathy from diabetes or tabes dorsalis, and syringomyelia (Fig. 14-16F).

Pilomotor reactions

Scratching the midaxillary skin produces pilomotor erection (gooseflesh). The normal response is abolished below the level of a transverse cord lesion. An exaggerated reaction may occur on the affected side in hemiplegia.

Blood pressure regulation

See Chapter 4. Orthostatic hypotension without tachycardia is common with autonomic nervous system diseases.

Bladder/bowel function

Patients with autonomic nervous system diseases often lose control of bladder and bowel function producing incontinence and/or urinary and fecal retention.

Some Peripheral Nerve Signs

Weak ankle plantar flexion—tibial nerve palsy (sciatic component)

The tibial nerve is the motor nerve to the gastrocnemius group and intrinsic muscles in the sole of the foot. Paralysis causes a calcaneovalgus deformity from the unopposed action of the dorsiflexors and evertors (Fig. 14-19A); plantar flexion and inversion of the foot are weak and the ankle jerk is absent. Since the nerve is sensory to the skin of the sole, damage results in an anesthetic sole vulnerable to pressure ulcers.

Weak ankle dorsiflexion—common peroneal nerve palsy (sciatic component)

The common peroneal nerve is the motor nerve to the muscles of the anterior and lateral compartments of the leg and the short extensors of the toes; it is sensory to the dorsum of the foot and ankle. Peroneal paralysis causes an equinovarus deformity with inability to dorsiflex the foot and toes, a foot drop (Fig. 14-28B). Anesthesia covers the dorsum of the foot and sometimes extends up the lateral side of the leg. The nerve is susceptible to pressure injury where it winds around the fibular head.

Lack of knee extension—femoral nerve palsy

The femoral nerve is the motor nerve for the quadriceps femoris. When the nerve is injured, patients cannot walk and standing is unstable. Extension of the knee is impossible (Fig. 14-19C). Anesthesia is widespread over the anteromedial aspect of the thigh, knee, leg, and the medial aspect of the foot.

Shoulder weakness—dorsal scapular nerve paralysis

The nerve supplies the rhomboids that elevate and retract the scapula. These muscles ascend obliquely from the medial border of the scapula to the spinous processes of the upper thoracic vertebrae. Although covered by the trapezius, they may be palpated when the shoulders are drawn backward.

Winged scapula—long thoracic nerve paralysis

The nerve supplies the serratus anterior that holds the scapula to the thorax. Paralysis produces a winged scapula (Fig. 13-32A) when the patient pushes forward against a wall.

Inability to initiate arm elevation in abduction—suprascapular nerve paralysis

The nerve supplies the supraspinatus and the infraspinatus. Paralysis results in weakness in the first 30 degrees of shoulder abduction and of external rotation. Wasting of these muscles is seen as depressions above and below the scapular spine.

Weak arm elevation in abduction—axillary nerve paralysis

The deltoid is paralyzed and atrophied. Elevation of the arm above 30 degrees in 90 degrees of abduction is impossible. A patch of sensory loss on the lateral aspect of the shoulder is often found. This can result from humeral neck fracture, shoulder dislocation, or scapular fracture.

Weak adduction and depression of the arm—anterior thoracic nerve paralysis

This nerve supplies the pectoralis major and minor. Paralysis is demonstrated when the patient presses the hands down on the hips (Fig. 14-29B).

Weak adduction and depression of the arm—thoracodorsal nerve paralysis

This nerve innervates the latissimus dorsi. Ask the patient to cough while grasping the posterior axillary muscle fold just below the scapular angle. With normal innervation the muscle will contract (Fig. 14-29C), a synkinesis.

Flail arm—brachial plexus injury

LMN paralysis of the brachial plexus may occur from forceful depression of the shoulder during birth (Erb–Duchenne paralysis) or a blow on the shoulder later in life. The arm hangs limply with the fingers flexed and turned posteriorly (Fig. 13-40). The biceps reflex is lost and there is muscle wasting.

Weak elbow flexion—musculocutaneous nerve paralysis

The biceps brachii and brachialis are supplied by this nerve. Paralysis can usually be demonstrated by inspection of the arm when the elbow is flexed against resistance. A small area of anesthesia occurs on the volar surface of the forearm.

Weak arm, wrist, and finger extension—radial nerve paralysis

Motor deficits depend upon the level of injury. Injury in the axilla causes paralysis of the triceps brachii, anconeus, brachioradialis, and extensor carpi radialis longus. A lesion at the level of the upper third of the humerus spares the triceps whereas damage between the humeral upper third and 5 cm above the elbow also spares the brachioradialis. Innervation of the wrist extensors may be injured at a lower level. Any lesion involving the extensor carpi radialis longus prevents fixation at the wrist in grasping, producing a wrist-drop (Fig. 14-30A). Paralysis of the extensor digitorum communis prevents extension of the wrist and fingers with thumb and finger drop. When the deep branch of the radial nerve is injured, radial deviation of the wrist may occur without wrist-drop. Sensory loss on the dorsum of the hand is quite irregular, but it usually includes dorsum of thumb to first phalanx and web (Fig. 14-30B). Injury commonly results from external pressure on the nerve in the spiral groove of the humerus (Saturday night palsy) or from fracture of the humerus.

Weak flexion of thumb and fingers—median nerve paralysis

The nerve is exposed to trauma in the antecubital fossa. It supplies the flexors of the wrists, digits, and forearm pronators: pronator teres, pronator quadratus, flexor carpi radialis, flexor digitorum sublimis, flexor digitorum profundus (except the fourth and fifth digits), flexor pollicis brevis, flexor pollicis longus, opponens pollicis, lumbrical, abductor pollicis longus, and brevis. All these muscles are innervated below the elbow. The most common site of median nerve entrapment is at the carpal tunnel (Carpal Tunnel Syndrome).

Weakness of finger adduction—ulnar nerve paralysis

The ulnar nerve is most vulnerable near the elbow where it curves posteriorly around the medial epicondyle. The chief motor disability from palsy is loss of the finer intrinsic motions of the hand. Inspection will show an abduction deformity of the little finger from paralysis of the interossei, interosseous muscle wasting, and partial clawhand from interphalangeal flexion deformities of the ring and little fingers.

Clawhand

An LMN lesion at the brachial plexus or ulnar nerve produces paralysis of the intrinsic hand muscles resulting in the clawhand. Sensation on the ulnar aspect of the arm, forearm, and hand may be lost.

Recurrent Headache Syndromes

Migraine

The pathogenesis is uncertain, but genetic factors are important. Some patterns have a defined genetic basis, for example, 50% of patients with familial hemiplegic migraine have an identified genetic abnormality. Spreading cortical depression is characteristic, perhaps initiated in the trigeminal projection system of the brainstem. Vascular constriction and dilation occur in many, but not all patients; constriction can rarely lead to ischemic cerebral events. Release of substance P and neurogenic inflammation may play a role. Serotonin, dopamine, and noradrenaline are all important in the migrainous process and their receptor blockers are used in treatment. It is a heritable disorder with periodic unilateral headache frequently preceded by an aura (classic migraine). Generalized throbbing headache is associated with nausea, light and sound sensitivity, and frequently allodynia ipsilateral to the headache. The prevalence of migraine is estimated to be up to 25% (more common in women than in men) in the United States. Patients with migraine have an increased incidence of Raynaud phenomenon. Onset is usually in adolescence, but may occur at any age; many have experienced motion sickness in childhood. The attacks occur from a few times a year to several times per week. Periods of frequent attacks may be separated by periods of none or few attacks. Often, migraine is coincident with some phase of the menstrual cycle. The clinical pattern varies so much among individuals that each individual must be considered separately. Persons with recurrent “sick” or “sinus” headaches, without definite documentation of infection, most likely have migraine [Goadsby PJ, Lipton RB, Ferrari MD. Migraine—Current understanding and treatment. N Engl J Med. 2002;346:257–270; Cady R, Dodick DW. Diagnosis and treatment of migraine. Mayo Clin Proc. 2002;77:255–261].

Migraine with aura (classic migraine)

Migraine with aura has four phases. The Prodrome: An attack is often triggered or preceded by a period of anxiety, tension, or sluggishness. Triggers include bright lights, loud noise, strong odors, skipped meals, various foods and beverages, and inadequate sleep. The Aura: A day or so before the attack, the patient may feel depressed or feel a sense of unusual well-being; occasionally, hunger is noted. Migrainous phenomena are typically unilateral, but are occasionally bilateral; the side may vary in different attacks. Patients tend to repeat their distinctive aura in successive attacks. A scintillating scotoma, usually involving both eyes, presents as flashing lights; sometimes there are black and white wavy lines, like the shimmering made by heat waves rising from pavement. Fortification spectra may be exhibited, with zigzag colored patterns with dark centers moving slowly across the visual field. Distinct patterns of the aura are associated with migraine variant syndromes (see Migraine Variants, below). Some patients have a typical aura without succeeding headache. Other neurologic symptoms occurring during the aura define special migraine syndromes discussed below. The Headache: The attack may begin any time of the day or night; it is frequently present on awakening. Usually, as the aura diminishes, unilateral headache appears on the side opposite to unilateral visual or somatosensory symptoms during the aura. The pain may start above one orbit and spread over the entire side of the head to the occiput and neck, or it may begin in the back of the head and move forward. Rarely, the site of pain is below the eye, in front of the ear, behind the mandibular angle, in the nape of the neck, or in the shoulders. Over an hour, the pain spreads and intensifies to a severe throbbing, boring, aching headache. Constant nonthrobbing pain occurs in 50% of patients. The pain is often augmented by reclining and lessened by sitting or standing. Shaking the head, coughing, or straining at stool intensifies the pain. Although the pain may be severe, it usually does not disrupt sleep. The pain is usually lessened by lying in a dark, quiet room. Nausea and, less commonly, vomiting often accompany the headache. Photophobia, phonophobia, and annoyance from odors (hyperosmia) are common during the headache. During the headache the patient may appear normal or be incapacitated with cold limbs and pale skin. Lacrimation, conjunctival injection, nasal congestion, and rhinorrhea are not rare, leading to the misattribution of “sinus headache.” The duration of the paroxysm is usually from 2 to 6 hours; it is relieved by sleep. The Recovery: When an attack terminates with sleep, the patient awakens without headache and experiences a sense of buoyancy and well-being. DDX: The diagnosis is easy in a long-established case with relatively typical symptoms. When the onset is recent and the symptoms unusual, other intracranial disorders must be excluded. Ophthalmoplegic migraine can simulate an aneurysm in the circle of Willis. Although hemiplegia can be a migrainous phenomenon, more serious causes should be sought.

Migraine variants

These variant forms of migraine are distinguished by the particular pattern of the aura.

Migraine without aura (common migraine)

The onset is slower than classic migraine and the duration is often longer, 4 to 72 hours. It may persist through sleep. The headache is unilateral or bilateral. In other respects, common and classic migraines are similar. There is considerable overlap of common migraine and tension type headache.

Ophthalmic migraine

This rare disorder may have scotomata that are succeeded by momentary blindness, anopsia, in the entire field, or in the lower or upper quadrants; or the pattern may be bitemporal or homonymous hemianopsia.

Ophthalmoplegic migraine

Transient unilateral paralysis of CN III (oculomotor) produces lateral deviation and ptosis. This occurs in young girls.

Basilar artery migraine

The scotomata and anesthesia of the face and limbs are bilateral, and vertigo or CN palsies may be present from brainstem nuclear ischemia. The transition from aura to headache may be accompanied by momentary loss of consciousness or light sleep.

Hemiplegic migraine

This is spectacular but rare. Paralysis is most likely to occur in migraine patients who experience paresthesias. The right side is more often involved. The patient complains of numbness or woodenness of the affected limbs. Although weakness may be the complaint, it may only be manifest by exaggerated deep tendon reflexes and Babinski sign. The paralysis lasts for 10 to 40 minutes, but may persist for 2 to 3 days; usually there are no permanent sequelae. The diagnosis is strongly supported by a family history of hemiplegic migraine.

Cluster headache

The headache is produced by dilatation of branches of the internal carotid artery, especially those supplying the meninges innervated by the trigeminal nerve. Although the syndrome can be simulated by the injection of histamine into the internal carotid artery, there is no conclusive evidence that histamine plays a role in the natural disorder. Cluster headache is five to six times more common in men than women with onset typically in the third or fourth decade of life. A family history of migraine or cluster headaches is not uncommon. Cluster headache is most commonly episodic occurring several times a day or week for several weeks, with long intermissions between episodes. However, it may be chronic with the cluster persisting for more than a year without intermission. The headache begins without aura and lasts 15 to 120 minutes (average 40 minutes). It is unilateral, severe, boring, and throbbing. It recurs consistently on the same side. It is usually maximal just inferior to the medial canthus of the orbit, but may occur in the temple or in the side of the face, and it may spread to the neck and shoulder. Flushing, edema and sweating of the skin, lacrimation, conjunctival injection, nasal congestion, rhinorrhea, partial Horner syndrome, and temporal artery dilatation may occur on the affected side [May A. Cluster headache: pathogenesis, diagnosis, and management. Lancet. 2005;366:843–855]. DDX: Paroxysmal hemicrania is briefer and more common in women; in Raeder syndrome, the pain is identical in quality but is persistent without discreet attacks; trigeminal neuralgia is much briefer lancinating pain, though overlap syndromes exist.

Paroxysmal hemicrania

The cause is unknown; women are more commonly affected than men. It is more often chronic than episodic. The headache is indistinguishable from cluster headache, but the pattern is distinct. Headaches are short, lasting on average 15 minutes, more frequent, up to 40 times per day, and uniformly abolished by indomethacin.

Tension-type headache

Though pain is attributed to sustained contraction of the neck, head, and shoulder muscles, this is unsubstantiated. Chronic intermittent headaches occur in the occiput and temporal regions, often with tenderness in the neck and trapezii. Usually the pain has recurred irregularly for many years, without periodicity. The sensation is described as mild or moderate discomfort, vise-like, a heavy feeling, a sense of pressure, a tight band, cramping, aching, or soreness; it is steady rather than throbbing. The pain is not augmented by coughing, straining at stool, or shaking the head. It usually begins in the occiput and extends upward to the temporal regions and down the nape of the neck to the shoulders. It may last for a few hours, with intensification near the day’s end; or it may persist for many days, waxing and waning throughout. The onset of an episode is often related to emotional strain or to occupational activity. The pain is relieved by external support of the head, the application of hot packs or massage to the neck and mild analgesics. Tenderness may be found in the upper border of the trapezii or the intrinsic neck muscles. DDX: The symptoms and signs are characteristic. Tension-type headaches are the only type not intensified by coughing or straining at stool; they are also the only type ameliorated by shaking the head. It is common to have features of both tension type and migraine headache.

Chronic daily headache—transformed migraine, rebound headache

Long-term use of analgesics leads to rebound headaches when medication use is interrupted for a few hours. This common cause of chronic daily headache occurs in patients with a history of tension-type or migraine headache who have developed daily persistent headache relieved only temporarily by medication. A history of regular daily use of prescription or over-the-counter analgesics and the absence of aura, neurologic findings, or other causes of headache are the keys to diagnosis. Overuse of caffeine in migraineurs will also precipitate chronic daily, rebound headaches. The treatment is complete abstinence from analgesics for 2 weeks. Migraineurs should not use analgesics more than 2 days a week.

Ice cream headache

See Chapter 7.

Traction, Displacement, and Inflammation Causing Intracranial Headache

The pain-sensitive intracranial structures are the dura and the arteries at the base of the brain, the cerebral arteries in the same region, the great venous sinuses, and certain nerves (CN V, -IX, -X, and C1–C3). The greater portion of the dura and cranium is insensitive. Mechanisms producing headaches from intracranial disorders include: (1) traction on the superficial cerebral veins and venous sinuses, (2) traction on the middle meningeal arteries, (3) traction on the basilar arteries and their branches, (4) distention and dilatation of the intracranial arteries, (5) inflammation near any pain-sensitive region, and (6) direct pressure or traction by tumors on cranial and cervical nerves. The resulting headaches may be throbbing when arteries are involved; otherwise the pain is steady. Headaches are often intensified by movements of the head, certain postures, and rapid changes in CSF pressure.

Brain tumor

Benign and malignant intracranial neoplasms compress and place traction on surrounding structures. Headache may be the first symptom. It can be intermittent or constant. The pain may be mild or excruciating and occur anywhere in the cranium. The headaches are not characteristic of any defined headache syndrome. Pulse synchronous tinnitus identifies the headache as caused by raised intracranial pressure. DDX: Brain tumor should be suspected whenever the onset is recent, pain is persistent and worsening rather than episodic, a recent change in the customary headache pattern has occurred, or an apparent migraine aura persists after the headache subsides.

• Meningitis. See CNS Infections.

• Brain abscess. See CNS Infections.

Lumbar puncture headache

CSF is lost through the puncture hole in the dura, decreasing the CSF volume. A few hours or days after a lumbar puncture, the patient develops a constant or throbbing, usually bifrontal or suboccipital, deep headache. Moderate neck stiffness may occur. The pain is intensified when standing, shaking the head, or with bilateral jugular vein compression. It is lessened by the horizontal posture and flexion or extension of the neck.

Idiopathic intracranial hypertension

Symptoms resemble those of a brain tumor. Elevated CSF pressure is found, with no structural abnormality. The typical patient is a young obese woman with recent rapid weight gain. Funduscopic examination reveals papilledema; if longstanding, the disks may be pale. Transient visual obscurations are common. Prevention of visual loss requires prompt diagnosis and therapy. The headache is much like common migraine except that it is often daily. Pulse synchronous tinnitus is commonly present and identifies increased intracranial pressure.

Intracranial Bleeding Headaches

Epidural hematoma

Trauma in a young person, before the dura is firmly attached to the skull, results in laceration of the middle meningeal artery and expansion of a hematoma between the skull and the dura. The lenticular hematoma compresses the brain. This is always the result of trauma. Pain is uniform and attributable to the skull fracture in the temporal parietal area. Loss of consciousness, progressive mental clouding, or focal motor or sensory defects suggests epidural hemorrhage; urgent head CT is mandatory.

Subdural hematoma

This is most common in older adults caused by a decrease in brain volume producing increased traction on the veins spanning the space between the mobile arachnoid and brain substance and the dural sinuses which at this age are fixed to the skull. Trauma leads to tearing of these small veins, producing low-pressure bleeding and slowly accumulating hematoma. After a severe head injury, the immediate accumulation of blood in the subdural space is not unexpected and offers no diagnostic difficulty. However, minor head trauma may be followed by a latent period of days, weeks, or months before the onset of headaches or other neurologic symptoms. The progression, timing, and attributes of the pain are similar to those of a brain tumor with relatively rapid expansion. Often no physical signs are present initially; later, localizing signs of an expanding intracranial mass become evident. Drowsiness, mental confusion, or coma may appear without headache or other signs, especially with bilateral frontal subdurals. The diagnosis is confirmed by CT or MRI imaging.

• Intracerebral hemorrhage. Hypertensive bleeding is usually from deep striatal vessels. The site is usually intracerebral; rarely is it subarachnoid. Cerebral amyloid angiopathy weakens vessel walls; it is associated with intracerebral hemorrhage without preceding hypertension. In approximately half the patients, the onset is marked by a sudden, severe, generalized headache, followed by rapidly evolving neurologic signs. Frequently, the patient vomits; often, there is nuchal rigidity. Seizures and/or coma may supervene. The sequence of events and the neurologic manifestations vary with the site and volume of hemorrhage. Putamen: A sensation of intracranial discomfort is followed in 30 minutes by dysphagia, hemiplegia, and sometimes anesthesias. Thalamus: Hemiplegia and hemianesthesias with dysphasia, homonymous hemianopsia, and extraocular paralyses are common. Cerebellum: Slowly developing, with repeated vomiting, occipital headaches, vertigo, paralysis of conjugate lateral gaze, and other ocular disorders. Pons: Prompt unconsciousness and death within a few hours. [Qureshi AI, Tuhrim S, Broderick JP, Batjer HH, Hondo H, Hanley DF. Spontaneous intracerebral hemorrhage. N Engl J Med. 2001;344:1450–1460] CLINICAL OCCURRENCE: Hypertension, aneurysm (traumatic, inflammatory, saccular or mycotic), angiomas, cerebral amyloid angiopathy, erosion from neoplasm, complicating cerebral infarction (embolism, thrombosis), hemorrhagic disorders, primary CNS lymphoma, and coagulation defects.

• Subarachnoid hemorrhage. Subarachnoid hemorrhage usually results from rupture of a saccular (berry) aneurysm of the circle of Willis. Often, rupture is preceded by leakage, in contrast to the rupture of an artery from hypertension. New onset of severe headache between age 14 and 50 should suggest a ruptured aneurysm; prompt diagnosis and therapy may be lifesaving. CN III signs may be seen and should always suggest a ruptured aneurysm; stiff neck may be present, but its absence does not exclude a ruptured aneurysm. The patient usually reports having the worst headache of his life. Excruciating generalized headache may be succeeded by nuchal rigidity, coma, and often death. Small hemorrhages may be missed, especially in patients with normal mental status, leading to adverse clinical outcomes [Kowalski RG, Claassen J, Kreiter KT, et al. Initial misdiagnosis and outcome after subarachnoid hemorrhage. JAMA. 2004;291:866–869; Edlow JA, Caplan LR. Avoiding pitfalls in the diagnosis of subarachnoid hemorrhage. N Eng J Med. 2000;342:29–36].

Other Headaches

Thunderclap headache

The sudden onset of a severe excruciating headache that at maximal intensity within seconds is often termed a thunderclap headache. A first severe headache meeting this description must be evaluated urgently. If accompanied by a change in the level of consciousness, nausea, visual changes, vertigo, paralysis, or paresthesias, the likelihood of a serious intracranial problem is increased [Linn FH, Wijdicks EF. Causes and management of thunderclap headache: a comprehensive review. Neurologist (United States). 2002;8:279–289]. CLINICAL OCCURRENCE: Classically, this is attributed to subarachnoid hemorrhage, but it may occur with intracerebral hemorrhage, migraine, cluster headache, stroke, with intercourse (coital headache), cerebral venous thrombosis, or cerebral vasoconstriction [Calabrese LH, Docick DW, Schwedt TJ, Singhal AB. Narrative review: reversible cerebral vasoconstriction syndromes. Ann Intern Med. 2007;146:34–44].

Hypertensive headache

The evidence points to segmental dilatation of branches of the external carotid artery. In patients with mild to moderate hypertension, the incidence and types of headache are no different than in normotensive persons. The diastolic pressure must exceed 120 mm Hg to cause headache. In accelerated hypertension without encephalopathy, half of the patients experience headache. The headaches are often occipital and there is no aura.

Headache present on awakening

Headaches present on awakening should suggest migraine, carbon monoxide poisoning, sleep apnea, and analgesic rebound headache. Tension headaches are not present on first awakening.

• Carbon monoxide poisoning. High levels of carboxyhemoglobin are formed by inhalation of carbon monoxide gas leading to decreased tissue oxygenation. This results from inhalation of combustion products in poorly ventilated spaces, for example, cars with malfunctioning exhaust systems, homes with malfunctioning gas furnaces or wood stoves, and burning charcoal in an enclosed space. Symptoms consist of headache, dizziness, nausea and vomiting, mental confusion, and visual disturbances progressing to obtundation, coma, and death. There is cherry-red skin and mucosa accompanied by a bounding pulse, hypertension, muscle twitches, stertorous breathing, and dilated pupils.

Giant cell arteritis

See Chapter 8.

Paranasal sinusitis

See Suppurative paranasal sinusitis. There is considerable debate as to the incidence of headache related to sinusitis. Many experts, based upon an extensive literature, believe that many, if not most of the conditions labeled “sinus headache,” are migraine [Schreiber CP, Hutchinson S, Webster CJ, Ames M, Richardson MS, Powers C. Prevalence of migraine in patients with a history of self-reported or physician-diagnosed “sinus” headache. Arch Intern Med. 2004;164:1769–1772]. Sinus and nasal symptoms are common in association with both migraine and cluster headache. No consensus has been reached [Cady RK, Dodick DW, Levine HL, et al. Sinus headache: a neurology, otolaryngology, allergy, and primary care consensus on diagnosis and treatment. Mayo Clin Proc. 2005;80:908–916].

Seizures

Seizures are caused by paroxysmal disordered electrical activity in the brain that may be focal, focal in onset with generalization, or generalized at the onset. Seizures are classified as generalized or partial. Partial seizures are those with a focal onset, regardless of whether they eventually generalize [Chabolla DR. Characteristics of the epilepsies. Mayo Clin Proc. 2002;77:981–990]. CLINICAL OCCURRENCE: Congenital: Congenital brain injury; Endocrine: Hypoglycemia; Idiopathic: Idiopathic epilepsy; Inflammatory/Immune: Vasculitis; Infectious: Meningitis, encephalitis, brain abscess, neurocysticercosis; Metabolic/Toxic: Fever, drug withdrawal (alcohol, barbiturates, benzodiazepines, anticonvulsant medications), amphetamines, cocaine, phencyclidine, theophylline, hypoglycemia, hypocalcemia, uremia, liver failure, hypoxia, penicillins and other b-lactams; Mechanical/Trauma: Head trauma; Neoplastic: Primary or metastatic cancer, insulinoma; Neurologic: Epilepsy, degenerative diseases of the CNS; Psychosocial: Drug abuse, physical abuse; Vascular: Stroke, vasculitis, hemorrhage.

Evaluation of a patient with seizure

When the patient has a seizure the immediate approach is to prevent injury and support cardiorespiratory function if necessary. However, the physician rarely observes the event, so a thorough history and examination are essential to identify the cause and to exclude other causes of impaired consciousness. In a patient treated for seizures, look for causes of relapse and evaluate adequacy of therapy. For patients with new onset of seizures, seek the cause, supplementing your neurologic examination with appropriate imaging and laboratory studies.

Partial seizures

Partial seizures begin within a specific brain region identified by the initial symptoms. They may remain localized, spread to a larger but limited area of the cortex, or progress to a generalized seizure involving both hemispheres. Partial seizures are classified as simple if the event is limited to a small portion of one cortex and consciousness is not altered. Complex partial seizures involve larger areas of the cortex and consciousness is impaired, although not lost.

Partial motor seizure

The seizures are caused by a focal lesion in the motor cortex. The seizure begins in a single body region with muscle twitching that becomes more violent with increasing amplitude. It may spread to contiguous muscle groups until the entire ipsilateral side is involved in clonic contractions. The seizure may stop at any stage of spread, or the contralateral side may be affected producing a generalized motor seizure. Consciousness is retained unless the attack is generalized.

Partial-complex seizure

The seizure often begins in the temporal lobe producing complex psychomotor symptoms, hence the old term temporal lobe seizures. They are often accompanied by an aura of an abnormal psychic event that can be olfactory, visual, or gustatory disturbances, or déjà vu. The attack may last from a few minutes to a few hours. Sudden but subtle loss of higher levels of consciousness occurs in which the patient is unaware of what transpires but retains motor functions and ability to react in an automatic fashion. The patient may respond to questions, but the answers disclose lack of understanding. This may be the only objective clue. Repetitive movements, which are often stereotyped, may be reported. Patients generally do not become violent or assaultive during an attack. Only occasionally are there tonic muscle spasms of the limbs. Amnesia for the attack is partial or complete. This condition should prompt a search for a focal lesion in the temporal lobe.

Secondary generalized seizure

Most major motor seizures begin from a unilateral small focus in one hemisphere then progress to involve the ipsilateral hemisphere and cross the corpus callosum to involve the contralateral hemisphere, producing a secondary generalized seizure. There may or may not be a warning or aura. Several hours or days before the attack a prodrome may be noted, with feelings of strangeness, dreamy states, increased irritability, lethargy or euphoria, ravenous appetite, feeling of impending disaster, headaches, or other symptoms. The prodrome is a partial seizure, and the patient learns its significance. The patient may experience vague epigastric sensations such as nausea or hunger and palpitation, vertigo, or sensations in the head. Any aura or focal seizure reflects focal brain disease. Consciousness is lost suddenly and simultaneously with the epileptic cry from sudden expulsion of air through the glottis. The patient is helpless and falls, often incurring injuries. Tonic spasm of all muscles occurs which may be so violent as to fracture bones. Breathing ceases from spasm of the thoracic muscles and cyanosis may be deep. Suddenly, the tonic state subsides, followed by clonic movements that increase in strength with repetition then cease. Foaming at the mouth is the result of forced expulsion of air and saliva. Clonic jaw movements cause biting of the tongue, cheeks, and lips. There may be involuntary defecation and urination. Unconsciousness usually lasts a few minutes, but may last hours. On return of consciousness, the patients are confused and amnestic for the seizure and preceding events, and complain of headache, stiffness, and sore muscles. Seizures are frequently followed by a deep sleep.

Generalized seizure

Generalized seizures involve the entire cerebral cortex at onset so they do not have an aura. History obtained from bystanders is critical in determining whether a seizure was generalized or focal at onset.

Absence seizure—petit mal

There is a sudden decrease in or loss of consciousness lasting up to 90 seconds, with no abnormal muscle movements; the patient’s eyes are wide open and staring. Full consciousness is rapidly and completely restored. Injuries may result from the momentary lapse, but not from falls since there is no loss of postural tone. The patient is vaguely aware of having “missed something.”

Major motor seizure—grand mal

This seizure is identical to the secondary generalized seizure except for the absence of an aura or any evidence of focal onset of the event. Consciousness is lost without warning and the patient is amnestic for the event.

Sudden Unexplained Death in Epilepsy (SUDEP)

There is an increased risk of sudden death in patients with epilepsy. The causes are not certain but may be linked to centrally triggered cardiac arrhythmias. Traumatic deaths including drowning are also increased.

Disturbances of consciousness may be classified according to severity. Lethargy is drowsiness caused by a condition other than normal sleep. Stupor is a somnolent state from which the patient may be momentarily aroused by questions or painful stimuli. Coma is the deepest state of unconsciousness in which the patient is motionless and unresponsive to stimuli. Syncope is a brief loss of consciousness that presents a different diagnostic problem from coma. Confusion denotes decreased attentiveness and may be present with any level of consciousness. The hallmark of confusional states is impaired perception, memory, and awareness of surrounding; delirium is confusion accompanied by hallucinations. Although delirium is sometimes accompanied by agitation and violent emotional responses, the patient may be quiet and withdrawn.

Narcolepsy

Narcolepsy is idiopathic or secondary to brain injury. There is impaired ability to voluntarily maintain wakefulness associated with immediate onset of rapid eye movement sleep. The idiopathic form usually occurs in young adults and may be associated with sudden loss of motor tone without loss of consciousness (cataplexy), inability to move upon awakening (sleep paralysis), and visual or auditory hallucinations at sleep onset (hypnagogic hallucinations) or on awakening (hypnopompic hallucinations). The patient experiences unexpected, inappropriate, and irresistible short spells of sleep. There may be several attacks per day with no deterioration of mentation.

Syncope

Syncope results from transient arrest of cerebral or brainstem functions. This usually results from momentary arrest of effective cerebral or brainstem perfusion. Impaired brain perfusion may occur from ineffective cardiac contraction (myocardial insufficiency or dysrhythmias), peripheral vasodilation producing hypotension, or from vascular reflexes. In the erect position, consciousness is lost when the mean arterial pressure declines to 20 to 30 mm Hg or when the heart stops for 4 to 5 seconds. In the horizontal position, more extreme conditions can be tolerated. The patient may complain of weak spells, light-headedness, or blackouts. A careful history must be obtained from both the patient and witnesses. The history and initial physical examination are of the greatest usefulness in establishing a specific etiology. Extensive investigations are unlikely to be useful, unless the history or examination direct you to a specific diagnosis [Kapoor WN. Syncope. N Engl J Med. 2000;343:1856–1862]. The most common cause of syncope is the vasovagal or vasodepressor faint. Other considerations are cardiac dysrhythmias (Adams–Stokes attacks—either tachy- or bradycardia), seizure, or autonomic dysfunction with orthostatic hypotension, pulmonary embolism, aortic stenosis, and cerebrovascular disease. Neurogenic causes can nearly always be differentiated with a good history or eyewitness report.

Neurocardiogenic syncope (vasovagal syncope, fainting)

Sudden vasodilation leads to decreased cardiac filling and forceful myocardial contraction on an underfilled ventricle. This triggers myocardial receptors that reflexively cause strong vagal outflow, leading to bradycardia, further hypotension, and syncope. With recumbency, the venous return improves and recovery ensues. The attack is induced in healthy persons by fear, anxiety, or pain. A hot environment, fatigue, illness, alcohol consumption, and hunger increase susceptibility. The patient usually has a prodrome that is brief and often begins with feeling light-headed and unsteady. Yawning, dimming of vision (as a consequence of the intraocular pressure collapsing arterioles), nausea and vomiting, and sweating are common. The face becomes pale or ashen. If the patient reclines promptly, the attack may be aborted. The syncopal stage consists of loss of postural tone and impaired consciousness. The patient falls to the floor either slowly or abruptly, usually avoiding injury. The patient may be confused but still hear voices and dimly see the surroundings. Complete unconsciousness lasts for a few seconds to at most a few minutes. Usually the muscles are utterly flaccid and motionless, although sometimes there are a few clonic jerks of arms and legs, but seldom a full tonic–clonic convulsion. Urinary or fecal incontinence is rare. Recovery follows assumption of the horizontal position. During recovery the patient remains weak, but is awake and lucid, the face gradually suffuses with pink, the blood pressure rises, the pulse becomes palpable and accelerated, the breathing deepens and quickens, the eyelids may flutter. The patient awakens with immediate awareness of the surroundings and memory for the prodrome. The muscle weakness persists for some time, so attempts to rise prematurely may induce another attack [Fenton AM, Hammill SC, Rea FR, Low PA, Shen WK. Vasovagal syncope. Ann Intern Med. 2000;133:714-725].

Orthostatic syncope

See Chapter 4. Normally, in the erect position pooling of blood in the legs is prevented by vasoconstriction mediated through the autonomic nervous system. When there is decreased intravascular volume or the compensatory mechanism is blocked, blood pools in the legs and arterial hypotension results. Distinctive features of autonomic insufficiency are normal heart rate, and absence of pallor and sweating. Recovery occurs in the horizontal position.

Adams-Stokes syndrome

The attacks of unconsciousness occur when effective cardiac contractions are absent for more than 5 seconds in the vertical position or 10 seconds in the horizontal. Usually, asystole results during the transition from a partial to a complete heart block or from the onset of paroxysmal tachycardia or ventricular fibrillation. When the heart rhythm is regular and the rate less than 40 per minute, heart block may be suggested by the variation in intensity of the first heart sounds. An ECG is required for confirmation. This form of syncope occurs in any position without a prodrome.

Valvular heart disease

Muscular vasodilation with exercise in patients with a fixed cardiac output leads to cerebral hypoperfusion and syncope. Exertion may induce typical syncope in a patient with aortic stenosis or, less commonly, aortic regurgitation or pulmonary hypertension.

Carotid sinus syncope

This occurs most commonly in patients older than 60 years with hypertension or occlusion of one carotid artery. Rotation of the head or a tight collar puts pressure on the carotid bulb, inducing vagal stimulation that results in one of three responses: (1) sinoatrial block, (2) hypotension without bradycardia, or (3) syncope with normal pulse rate and blood pressure. Syncope related to specific neck movements suggests carotid sinus syncope. Carotid sinus massage is dangerous and should not be used to test the diagnosis as cerebral infarction and death have resulted from this maneuver. Never palpate both carotids simultaneously. DDX: Rotation of the neck may precipitate syncope in patients with severely impaired vertebrobasilar circulation.

Hyperventilation

Hyperventilation results in hypocapnea that induces diminished cerebral blood flow. Before the attack, the patient is usually anxious or emotionally upset. The patient feels tightness in the chest or suffocation accompanied by numbness and tingling of arms and face, sometimes with carpopedal spasm. Loss of consciousness may be prolonged compared with most other types of syncope. The symptoms are reproduced by having the patient overventilate. Rebreathing into a paper bag will arrest the attack and demonstrate a method of self-treatment.

Cough syncope

Severe paroxysms of coughing, laughing, or vomiting may induce syncope; this is rare in women. The history is usually diagnostic. The mechanism is disputed.

Micturition syncope

Voiding a large volume, particularly after arising from a warm bed, may precipitate syncope. Similarly, rapid decompression of an overfilled bladder by catheterization or the removal of large volumes of ascitic fluid may also cause syncope.

Akinetic epilepsy

Common features in akinetic epilepsy, but rare in syncope, are lack of pallor, sudden onset without prodrome, injury from falling, tonic convulsions with upturned eyes, urinary or fecal incontinence, and postictal confusion with headache and drowsiness.

Hysterical syncope

This is the swoon of Victorian novels. It occurs in the presence of witnesses. The fall is graceful and harmless. The skin color, heart rate, and blood pressure are all normal. The patient lies motionless or makes resisting movements.

• Coma. Coma results from serious disruption of brain function that impairs the reticular activating system such that consciousness is lost. Coma is a state of prolonged unconsciousness. Since the patient cannot give a history or cooperate, the examination requires a special approach. The correct diagnosis can be rapidly established in most cases by a structured complete physical and neurologic examination and use of radiologic and laboratory testing. Two axioms must always be kept in mind. (1) Finding one cause for coma is not sufficient. For instance, a comatose patient with alcohol on the breath may have sustained a head injury while intoxicated; a person injured in an automobile accident may have had an antecedent stroke leading to the accident; or an unconscious patient with a few sedative tablets at the bedside may have taken the drug for symptoms of meningitis or brain tumor. (2) A complete neurologic examination is necessary but not sufficient. All other systems must also be assessed: finding atrial fibrillation raises the possibility of cerebral embolism; the retinae may contain signs of diabetes; demonstration of a consolidated lung suggests lobar pneumonia or pneumococcal meningitis; abdominal examination has discovers a distended bladder, leading to a diagnosis of uremia from bladder outlet obstruction. The differential diagnosis and management of coma is beyond the scope of this text. The reader should consult textbooks of medicine, neurology, and emergency medicine.

History of the comatose patient

Interview the relatives, acquaintances, attendants, or police officers who discovered the patient. Circumstances of Discovery: How was the patient found? Were there any drugs or poisons nearby? Do the surroundings suggest poisoning from carbon monoxide or other fumes? Was there evidence of trauma? What was known about the patient’s antecedent intake of food and fluids? Who prepared the food? What were the symptoms and actions before the onset of coma? Did the patient have pain, diarrhea, or vomiting? Past History: Was the patient known to have epilepsy, diabetes, hypertension, or alcohol or drug addiction? Did the patient have suicidal thoughts? Was the patient ever hospitalized in a mental institution? Was the patient known to be taking medicines? Had there ever been operations for malignancy? Has this happened before?

Physical examination of the comatose patient

Assess patency of the airway and the presence of adequate respirations and pulse. Vital Signs: Note any abnormalities. General Inspection: Note posture; look for tremors or muscle jerks; inspect the respiratory movements for bradypnea, tachypnea, Kussmaul breathing, Cheyne–Stokes breathing. Color: Look for pallor, icterus, the cyanosis of methemoglobinemia, the cherry-red color of carbon monoxide hemoglobin. Scalp and Skull: Look for contusions, lacerations, gunshot wounds; palpate for depressed skull fractures and inspect the mastoid for hematoma of basilar skull fracture (Battle sign). Eyes: Inspect for periorbital bruising (raccoon sign) of basilar skull fracture. Lift the eyelids and let them close; lagging of one lid suggests hemiplegia. The patient with hysteria resists opening by closing the lids tighter. In coma, the eyes remain fixed or oscillate slowly from side to side; oscillation is lacking in hysteria in which the eyes may wander but fix momentarily. Conjugate deviation of the eyeballs is toward the affected side in destructive lesions of the frontal lobe, away from the affected side in irritative lesions. The presence of extraocular muscle palsies assists in localizing an intracranial lesion. After confirming the absence of neck injury, open the eyelids and quickly turn the head from side to side. The eyes of the comatose patient with cerebral damage turn in the opposite direction in a conjugate movement if the brainstem is intact (doll’s eyes). This oculocephalic reflex is lost with lesions of the pons or midbrain. Caloric studies, in which you test an oculovestibular reflex, provide information of similar significance. These are performed by irrigating the ear canal with 30 to 50 mL of ice water and noting that, with cerebral dysfunction and an intact brainstem, a tonic conjugate deviation of the eyes toward the cold ear lasts for 30 to 120 seconds. Bilateral, widely dilated pupils occur in profound posttraumatic shock, massive cerebral hemorrhage, encephalitis, poisoning with atropine-like drugs, and the end stages of brain tumor. Bilateral pinpoint pupils suggest opiate poisoning or a pontine hemorrhage. A unilateral unreactive pupil indicates a rapidly expanding lesion on the ipsilateral side, as in subdural or middle meningeal epidural hemorrhage or brain tumor. Examine the fundi for the exudates and hemorrhages, and the choked disks of increased intracranial pressure. Facial Muscles: Asymmetry of the face may indicate hemiplegia. The mouth droops on the affected side; the cheek puffs out with each expiration. Painful pressure on the supraorbital notch causes the mouth to grimace in an asymmetric pattern to reveal the weak side. Oral Cavity: Examine the tongue for lacerations from biting during a seizure. Look for a diphtheritic membrane, other signs of pharyngitis, or ulceration or discoloration from poisons. Breath: Smell the breath for acetone, ammonia, alcohol or its successor aldehydes, paraldehyde, and other odors. Ears: Look for pus, spinal fluid, or blood emerging from the external acoustic meatus or blood behind the drum from basilar skull fracture. Neck: Test for nuchal rigidity, Kernig sign, and Brudzinski sign, all signs of meningeal irritation. Chest: Percuss and auscultate the chest for pneumothorax, consolidation, wheezing, or crepitation. Heart: Auscultate for rhythm, rate, and strength of the heart sounds and any abnormal sounds. Abdomen: Auscultate for bruits and palpate for masses or rigidity suggesting peritonitis or fluid. Limbs: Test each limb successively for flaccidity by lifting it and letting it fall to the bed. If any muscle tone is retained, a difference in the two sides indicates a hemiplegia. The reflexes on the paralyzed side are absent during the stage of spinal shock, but in deep coma, all reflexes are lost. In deep coma, the Babinski reflex is present bilaterally, so it cannot be employed to localize a lesion. If some reflexes are retained, a difference in the two sides is significant. Sensory Examination: Only the responses to painful stimuli can be evaluated. The patient will show defensive reactions when pricked in sensitive areas, but no response is forthcoming when analgesic regions are stimulated. If the stimulated region is sensitive but paralyzed, a defense or withdrawal movement may occur on the opposite side; the facial expression will indicate pain. Deep pressure sense should be tested by compression of the Achilles tendon, the testis, and the supraorbital notch.

Classify the seriousness of cerebral dysfunction with the Glasgow Coma Scale (Table 14-1) in which mild is 13 through 15, moderate is 9 through 12, and severe is 3 through 8 points. Patients with scores <8 are in coma [Booth CM, Boone RH, Tomlinson G, Detsky AS. Is this patient dead, vegetative, or severely neurologically impaired? Assessing outcome for comatose survivors of cardiac arrest. JAMA. 2004;291:870–879]. An alternative coma scoring system has been proposed and validated by one group, the Full Outline of UnResponsiveness (FOUR) Score (Table 14-2). It can be used in patients on ventilators and has high interobserver reliability [Iyer VN, Mandrekar JN, Danielson RD, Zubkov AY, Elmer JL, Wijdicks EF. Validity of the FOUR Score Coma Scale in the medical intensive care unit. Mayo Clin Proc. 2009;84:694–701].

Differential diagnosis of coma

The multiple etiologies of coma can be conveniently divided into three categories, which may be suggested by history and physical examination findings.

Metabolic encephalopathy

Metabolic derangements or toxin exposure impairs brain function and leads to coma. Coma occurs with normal pupillary responses, normal brainstem reflexes, and no focal neurologic deficits. Asterixis, myoclonus, and Cheyne–Stokes respiration occur. CLINICAL OCCURRENCE: Hypoglycemia, hypoxia, hypercarbia, hyponatremia, intoxications (e.g., alcohol, benzodiazepines, barbiturates, opiates), hepatic insufficiency, advanced kidney failure, severe hypothyroidism, and many others.

Hypoglycemic coma

The prodrome may resemble a vasovagal spell but confusion is prominent. The syncopal stage is frequently prolonged and loss of consciousness is usually incomplete. Instead, there is muscle weakness with mental confusion. The blood sugar is usually below 30 mg/100 mL; the symptoms are relieved by the intravenous administration of glucose or injection of glucagon.

Transtentorial herniation

An expanding supratentorial mass forces the uncus to herniate. Typically, the uncus of the temporal lobe compresses the third nerve and then the midbrain initially producing focal deficits. Progression from the focal deficits to coma and death can be rapid. CLINICAL OCCURRENCE: Brain tumor (primary or metastatic), bleeding (intracerebral, subdural, epidural), cerebral edema associated with infarction (arterial or venous), abscess, encephalitis, or massive liver necrosis.

Brainstem injury

The brainstem reticular activating system that runs from the upper pons to the lower diencephalon is responsible for maintaining consciousness; damage results in coma. The onset is usually abrupt, either following trauma or acute severe headache. Emergent neuroimaging is required. CLINICAL OCCURRENCE: Trauma and spontaneous hemorrhage are the most common etiologies.

Chronic vegetative state

This condition results from severe injury to the cortex, thalamus, and/or white matter of the brain. The clinical syndrome is wakefulness and sleep without awareness or responsiveness to the environment. The cycling of wakefulness and sleep is distinct from coma [Bernat JL. Chronic disorders of consciousness. Lancet. 2006;367:1181–1192].

Minimally conscious state

These patients show some awareness behaviors and imaging suggests that some may have considerable awareness without the ability to respond akin to the locked in state. Clinicians should always assume that even apparently comatose patients are able to perceive what is done to them and hear and comprehend what is said at the bedside. The prognosis is very difficult to predict.

Transient ischemic attack

Transient ischemic attack (TIA) results from a failure of perfusion because of hemodynamic causes or microembolism. Less common causes are in situ arterial thrombosis, arterial dissection, and venous sinus thrombosis. The symptoms reflect the area of ischemia. TIA is, by definition, the acute onset of a focal neurologic deficit in a specific vascular distribution with full recovery within 24 hours. Neurologic signs are absent between attacks. The correct diagnosis and prompt evaluation of TIA are important because it is an indication of possible impending cerebral infarction: up to 25% of patients with a new TIA will have a stroke within 24 hours [Johnston SC. Transient ischemic attack. N Engl J Med. 2002;347:1687–1692]. The risk for stroke within 7 days of a TIA is predicted by a simple clinical score (ABCD²) based upon age, blood pressure, clinical features, duration, and diabetes [Johnston SC, Rothwell PM, Nguyen-Huynh MN, et al. Validation and refinement of scores to predict very early stroke risk after transient ischaemic attack. Lancet. 2007;369:283–292; Sanders LM, Srikanth VK, Blacker DJ, Jolley DJ, Cooper KA, Phan TG. Performance of the ABCD² score for stroke risk post TIA: meta-analysis and probability modeling. Neurology. 2012;79:971–980]. DDX: Diplopia, syncope, transient confusion, and paraparesis are uncommon symptoms of TIA. The differential diagnosis of TIA includes convulsions, syncope, migraine, focal cerebral masses, such as subdural hematomas, cardiac diseases, and labyrinthine disorders.

Carotid artery TIA

Symptoms and signs are related to the ipsilateral cerebral hemisphere and/or retina. Findings include contralateral weakness, clumsiness, numbness of the hand, hand and face, or entire half of the body, dysarthria, aphasia, and ipsilateral amaurosis fugax with monocular visual loss, usually described as a shade coming down. Visual loss may be complete blindness or sector visual loss. Carotid bruits or retinal emboli may be found.

Vertebrobasilar artery TIA

Symptoms and signs are related to the posterior circulation and may affect vision and cranial nerve functions. Frequent complaints are combinations of binocular visual disturbance or loss, vertigo, dysarthria, ataxia, unilateral or bilateral weakness, or numbness and drop attacks (sudden loss of postural tone and collapse, without loss of consciousness).

Ischemic stroke

Arterial obstruction by thrombosis, embolism, or dissection produces tissue ischemia resulting in neuronal infarction. The area of infarction is surrounded by a penumbra of ischemic tissue which is salvageable with prompt restoration of perfusion. Ischemic stroke is painless and the patient remains conscious. Symptom onset may be abrupt or stuttering (see TIA). The specific symptoms reflect the functional loci within the distribution of the affected vessel [Goldstein LB, Simel DL. Is this patient having a stoke? JAMA. 2005;293:2391–2402]. The middle cerebral artery is most commonly affected with the arm more severely affected than the leg. With anterior cerebral artery stroke, the leg is more affected than the arm. Posterior cerebral strokes result in homonymous hemianopsia. Basilar artery strokes are frequently associated with vertigo, diplopia, dysarthria, or Horner syndrome; hemiparesis is not a feature. Cerebral venous sinus thrombosis presents with symptoms and signs of cerebral vascular disease with less discrete evidence of focal lesions [Stam J. Thrombosis of the cerebral veins and sinuses. N Engl J Med. 2005;352:1791–1798; Thaler DE, Frosch MP. Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Case 16–2002. A 41-year-old woman with global headache and an intracranial mass. N Engl J Med. 2002;346:1651–1658]. The National Institutes of Health Stroke Scale (Table 14-3). This is the preferred tool for evaluating the severity of initial stroke symptoms and signs and response to therapy.

Middle cerebral artery—hemiparesis

Paresis of either the right or left side of the body indicates contralateral disease of the brain or ipsilateral high spinal disease. The most common cause is vascular occlusion of the middle cerebral artery. Paralysis is partial or complete. Sensory loss occurs in the same distribution. Consciousness is not impaired. The patient may not be aware of the deficit with right-sided infarcts. Lesions in the left hemisphere often affect Broca area disrupting fluent speech while comprehension remains intact. If the visual pathways are affected, a homonymous hemianopsia will be found. DDX: Conversion Reaction: In patients with complaints of unilateral weakness or paralysis of the legs but confusing findings, try to elicit the Hoover sign, which depends on the absence of a normal associated movement (synkinesia). Place the patient supine, stand at the foot of the table, and place a palm under each heel. Ask the patient to raise the affected limb (Fig. 14-13D). In organic disease, the unaffected limb will press downward in the effort to raise the affected limb, it is absent in conversion reaction. The sign is helpful only when the patient has, or claims to have, paralysis of one leg. Paraplegia must be excluded. Hysterical arm paralysis may be identified by dropping the flaccid arm onto the face. With organic paralysis, the arm will strike the face; in hysteria, it always misses.

• Cavernous sinus thrombosis. Thrombosis with occlusion of the cavernous sinus results from bacterial infection of the upper lip, tooth socket, eyes, or face. Patients present with pain in the eye and forehead, chills, fever, and impaired vision. Physical findings include chemosis, edema of the eyelids, exophthalmos, hyperemia, papilledema, orbital tenderness, and CN palsies of CN III, -IV, and -VI. Progression leads to leptomeningitis, blindness, intracerebral abscess, septicemia, and death.

Parkinson disease and parkinsonism

Parkinson disease is caused by depletion of the dopaminergic neurons of the substantia nigra leading to decreased dopamine delivery to the striatum. Parkinson disease is one of a family of conditions affecting the extrapyramidal motor system and presenting with abnormalities of posture and movement. The onset of Parkinson disease is asymmetric and gradual; familial forms exist. Tremor is present is two-third of patients, usually beginning in one hand. It is a slow (~6 Hz) repose tremor absent with movement and sleep. Other classic features are slowed voluntary movements (bradykinesia leading to masked face), rigidity, postural instability, and a gait marked by small steps (march au petit pas) with difficulty lifting the feet, absent arm swing, difficulty turning smoothly, and a tendency to fall forward (festinating gait). Features that may be found early in the disease, if sought, include micrographia, decreased blink rate, and anosmia. Cognitive and emotional disturbances are late findings [Rao G, Fisch L, Srinivasan S, et al. Does this patient have Parkinson disease? JAMA. 2003;289:347–353]. DDX: Absence of tremor, though not rare, should raise the suspicion for one of the other Parkinsonian syndromes. Early cognitive or emotional instability, fluctuating mental status, and hallucinations suggest Lewy body disease. Symmetrical onset without tremor but with eye findings, particularly paralysis of upward gaze, and falls suggest Progressive Supranuclear Palsy. Orthostatic hypotension, urinary incontinence, and dysarthria, also without tremor, should suggest Multisystem Atrophy (Shy–Drager Syndrome). Drug-induced Parkinsonism is common with metoclopramide and the antipsychotics most commonly described.

Multiple sclerosis

Multifocal demyelination occurs in the nervous system presumed to be mediated by autoimmune mechanisms. The onset is usually abrupt over hours to a few days, with remissions occurring over weeks, if at all. Optic neuritis with transient visual loss lasting weeks to months is a common presenting symptom. Other symptoms include incoordination, paresthesias, weakness, and loss of sphincter control. The signs depend upon the location of the demyelinating lesion(s): ataxia, dysarthria, intention tremor, ocular palsies, visual loss, hyperactive deep reflexes, diminished abdominal reflexes, and trophic changes in skin. The Charcot triad of signs is intention tremor, nystagmus, and scanning speech. The disease may be progressive from onset with inexorable loss of function, or relapsing–remitting with complete resolution of the symptoms and signs between relapses. Many patients with initially relapsing–remitting disease will progress to chronic progressive disease with incomplete remissions of each relapse.

Neuromyelitis optica—Devic syndrome

IgG antibodies to a unique class of CNS membrane aquaporin is thought to be the cause. Symptoms are visual loss and paresthesias, painful spasticity and weakness in the arms and legs.

• Meningitis. Headache is a prominent early symptom of meningitis. It is generalized, throbbing or constant, and accompanied by fever and stiff neck. Because the meninges are inflamed, the headache is intensified by sudden movements of the head. The headache may be accompanied or followed by drowsiness or coma. Signs of meningeal irritation are nuchal rigidity and Kernig and Brudzinski signs. Although many febrile illnesses are accompanied by some degree of head pain, the headache of meningitis is especially severe. When headache is associated with stiff neck, a lumbar puncture is indicated [Attia J, Hatala R, Cook DJ, Wong JG. The rational clinical examination. Does this adult patient have acute meningitis? JAMA. 1999;282:175–181]. Viral meningitis causes headache that is generally less severe and more gradual in onset; the distinction cannot be made clinically.

• Brain abscess. The brain parenchyma contains an encapsulated infection consisting of liquefied brain and pus. Infection is either hematogenous or from local extension. Symptoms and signs of brain mass appear coincident with or after infection in the ears, paranasal sinuses, lungs or, rarely, osteomyelitis, or other source. When the primary infection has not been recognized, the distinction from brain tumor may not be evident until imaging is obtained. Less than half the patients with brain abscess exhibit the classic triad of fever, headache, and focal deficit. CLINICAL OCCURRENCE: Direct Extension: From otitis or sinusitis; Hematogenous: Pneumonia, endocarditis (especially Staphylococcus aureus), osteomyelitis, other bacteremias (patients with cyanotic congenital heart disease and right-to-left shunts are particularly susceptible), systemic arteriovenous malformations; Penetrating Trauma: After neurosurgery, gunshot wounds, open skull fractures.

Neurosyphilis

Chronic infection with Treponema pallidum produces degeneration of the spinal cord posterior columns, dorsal roots, and dorsal root ganglia. Brain infection produces a tertiary syphilis syndrome of degenerative brain disease. The patient is often unaware of having been infected and, with many years intervening, the history of a chancre may be lost. Other signs of tertiary syphilis may be present, such as aortitis with aortic insufficiency and gumma formation. Two CNS syndromes are recognized.

Tabes dorsalis

Spinal cord involvement produces lightning-like pains in the trunk and lower limbs, paresthesias, urinary incontinence, and impotence. There is loss of position sense, ataxic wide-based gait, footdrop, and loss of reflexes. Loss of position sense leads to joint destruction with Charcot deformities. Tabetic crisis is abdominal pain and vomiting with a relaxed abdominal wall.

General paresis

The brain findings can be recalled using the pneumonic PARE-SIS: Personality, Affect, loss of Reflexes, Eye findings (Argyll Robertson pupil), Sensory changes, Intellectual deterioration (dementia precox), and Speech changes.

• Rabies. Infection by this neurotropic virus is transmitted by the bite of infected mammals. Onset is marked by local dysesthesia radiating from the site of entry, malaise, nausea, and sore throat. Later, restlessness and hallucinations occur. There is hyperesthesia of the wound and later, dysarthria, dysphagia for fluids, convulsions, delirium, and opisthotonos stimulated by lights or noises. Breathing becomes shallow and irregular with hoarseness or aphonia. The stretch reflexes are hyperactive and there is nuchal rigidity, Babinski sign followed by flaccid paralysis and death. A high index of suspicion is required to make the diagnosis and to protect contacts to body fluids. Many patients diagnosed in the United States do not have an identified source of infection; bats are the most common identified source.

Paraparesis

Loss of motor power to both legs indicates a transverse lesion of the spinal cord. The level is determined by the sensory findings. Frequent causes of paraparesis are trauma and transverse myelitis, which may follow several different types of viral infection. Extrinsic cord compression by herniated disk, epidural abscess, or neoplasm are less common but potentially treatable. Dural arteriovenous malformations cause venous congestion and spinal cord ischemia without infarction; the deficits are fully reversible if the diagnosis is made and the malformation closed [Atkinson JLD, Miller GM, Kraus WE, et al. Clinical and radiographic features of dural arteriovenous fistula, a treatable cause of myelopathy. Mayo Clin Proc. 2001;76:1120–1130].

Hemisection of the spinal cord—Brown-Sequard syndrome

Hemisection of the cord damages the ipsilateral descending motor pathways and ascending proprioceptive pathways (cross in the brainstem), and the contralateral sensory pathways for pain and temperature (cross at their spinal root levels). Patients have motor paralysis with spasticity and loss of proprioception on the side of the lesion and absent pain and temperature sensation on the opposite side, below the level of the injury.

Quadriparesis

Paresis or paralysis of all limbs without changes in consciousness indicates impairment of the descending corticospinal (pyramidal) tracts. The most common cause is traumatic injury to the cervical spine; in this case the bulbar muscles are spared. Less common causes, usually with some bulbar involvement, are multiple sclerosis, primary motor system disease, and botulism. Onset of nontraumatic generalized weakness or paralysis over a few hours or days suggests an electrolyte disturbance (most commonly severe hypokalemia). In the hospital, other causes to be considered are inadvertently high spinal anesthesia, paralytic drugs, and the polyneuropathy of severe illness.

Syringomyelia and Chiari malformations

There is cavitary expansion within the cervical spinal cord that damages the centrally crossing sensory tracts and the pyramidal tracts. The cause is unknown. Syringomyelia is frequently associated with herniation of the cerebellar tonsils through the foramen magnum (Chiari type 1). Patients present with decreased pain and temperature sensation in the arms and shoulders, LMN weakness in the arms and UMN weakness with spasticity in the legs. Chiari type 2 malformation (incomplete closure of the spinal canal) is always accompanied by myelomeningocele.

Amyotrophic lateral sclerosis

Degeneration of upper and LMNs leads to progressive weakness and muscle wasting. The disease begins gradually, proceeds progressively, and ends fatally, usually in 2 to 3 years. Muscle aches and cramps are accompanied by weakness of distal upper limbs, spreading to the lower extremities. Dysarthria, dysphagia, and drooling indicate bulbar involvement. Muscle fasciculation and severe wasting are seen, especially in upper limbs. Fasciculations may be evident in the tongue. Hyperreflexia and spasticity of lower limbs indicate UMN involvement [Rowland LP, Shneider NA. Amyotrophic lateral sclerosis. N Engl J Med. 2001;344:1688–1700; O’Neill GN, Gonzalez RG, Cros DP, Ackerman RH, Brown RH Jr, Stemmer-Rachamimov A. Case records of the Massachusetts General Hospital. Case 22–2006: a 77-year-old man with rapidly progressive gait disorder. N Engl J Med. 2006;355:296–304].

Posterior column disease

Deficiencies of vitamin B₁₂ and copper and neurosyphilis (tabes dorsalis) lead to degeneration of the posterior columns with loss of proprioception in the lower extremities leading to abnormalities of gait and balance. Nitrous oxide anesthesia may precipitate severe B₁₂ deficiency in patients with minimal stores. DDX: Glossitis, macrocytic anemia, and dementia accompany severe B₁₂ deficiency; a spastic gait disorder may accompany copper deficiency [Kumar M. Copper deficiency myelopathy (human swayback). Mayo Clin Proc. 2006;81:1371–1384].

Neuropathies are classified as axonal if the nerve cell axon is primarily involved, or demyelinating if the lesion is in the myelin coating of the nerve. Single nerve trunk lesions may be traumatic, ischemic, or inflammatory. Peripheral nerve dysfunction in the absence of CNS disease is common. Patients present with complaints of numbness, burning, unsteadiness (often described as dizziness), falling, or weakness. Physical examination may show sensory impairment (pressure, vibration, position, pain, and temperature or simple touch depending on the size of nerves involved), muscle weakness and wasting with fasciculations, and/or diminished reflexes. Release signs are not present and plantar response is flexor. Demyelinating neuropathies present acutely or more slowly with involvement of both motor and sensory nerves; often the motor component dominates with weakness and areflexia. They may involve any nerve at any level from root distally so the pattern is usually asymmetrical and involves proximal as well as distal muscles. Axonal neuropathies are diffuse, symmetrical, slowly progressive and usually sensory at onset with later involvement of motor nerves; they are primarily distal and progress proximally affecting the feet before the hands. Isolated nontraumatic involvement of all components of a single nerve is called mononeuritis multiplex, usually resulting from an inflammatory lesion causing ischemia; recovery is common and complete [Hughes RAC. Peripheral neuropathy. BMJ. 2002;324:466–469; Poncelet AN. An algorithm for the evaluation of peripheral neuropathy. Am Fam Physician. 1998;57:755–764]. CLINICAL OCCURRENCE: Congenital: Charcot–Marie–Tooth disease, porphyria, Fabry disease, familial neuropathy; Endocrine: Diabetes; Idiopathic: ICU polyneuropathy, idiopathic polyneuropathy; Infectious: Leprosy, rabies (early at inoculation site), postherpetic neuralgia; Inflammatory/Immune: Acute and chronic inflammatory demyelinating polyneuropathy, vasculitis, SLE, amyloidosis, celiac disease, monoclonal gammopathy; Mechanical/Trauma: Contusion and laceration, repetitive use, vibration (e.g., jackhammers, pneumatic drills), cold injury (chilblains and frostbite), electrical injury; Metabolic/Toxic: Amyloidosis, porphyria, diabetes, Fabry disease, poisoning (arsenic, other heavy metals, pyridoxine), drugs (e.g., vincristine), nutritional deficiency (vitamins B₁₂, copper, and B₆); Neoplastic: Paraneoplastic syndromes, metastatic invasion of nerves; Psychosocial: Substance abuse producing unconsciousness with pressure-induced ischemia; Vascular: Vasculitis.

Diabetic neuropathy

Diabetes types 1 and 2 are associated with peripheral nerve injury with a latency of approximately 15 years from onset for type 1. Damage is thought to be metabolic in most forms, and ischemic in the acute reversible forms. Several forms of diabetic neuropathy are recognized.

Distal sensorimotor axonal neuropathy

This is most common, presenting as numbness or burning pain in the feet and progressing proximally with loss of protective sensation, trophic skin changes, pressure-induced ischemic ulceration, and infection leading to amputation, if preventive measures are not taken. Limbs at risk are insensitive to a 10-g monofilament test [Smieja M, Hunt DL, Edelman D, Etchells E, Cornuz J, Simel DL. Clinical examination for the detection of protective sensation in the feet of diabetic patients. International Cooperative Group for Clinical Examination Research. J Gen Intern Med. 1999;14:418–424]. In severe forms, muscle wasting and Charcot joints occur.

Autonomic neuropathy

This late onset neuropathy frequently involves the stomach with gastroparesis and delayed gastric emptying which may make control of blood sugars very difficult. Sudomotor injury contributes to skin fragility and ulceration. Impotence is common and colon and bladder dysfunction not rare. The sensorimotor and autonomic neuropathies are delayed or prevented by tight control of blood glucose.

Diabetic amyotrophy or polyradiculopathy

This is an acute, painful, inflammatory, or ischemic injury to one or more spinal roots. Patients present with severe back, chest, abdominal or proximal leg pain, and progressive weakness and may have bowel and bladder dysfunction. It is usually acute in onset and asymmetric. Recovery is expected over months in most people.

Cranial nerve paralysis

This is not uncommon and often mistaken for much more serious intracranial pathology. CN III, -IV, and -VI are most often involved. The pupil is spared in CN III lesions. Diabetic amyotrophy and CN lesions are not clearly related to the duration of diabetes or degree of blood sugar control.

Acute inflammatory demyelinating polyneuropathy (AIDP)—Guillain–Barre syndrome

This is an immune-mediated demyelinating disorder occurring 1 to 3 weeks after viral infection, Campylobacter jejuni gastroenteritis, or, rarely, after surgery or with malignant lymphoma. There is usually rapidly progressive ascending flaccid paralysis with pain in the back and limbs. Nausea and vomiting can occur. There are diminished deep and superficial reflexes, and distal numbness and tingling. CN involvement causes dysphasia, dysphagia, and dysarthria. With chest wall involvement, respiratory failure supervenes.

Inflammatory demyelinating polyneuropathy (CIDP)

There is chronic immune-mediated demyelination of nerve roots, plexuses, and peripheral nerves. Multiple nerves may be involved often in an asymmetric pattern. Onset is sudden or gradual with motor and sensory symptoms and signs referable to a spinal root, plexus or peripheral nerve. Symptoms may progress gradually or remit and relapse. Weakness and areflexia accompany sensory findings indicating involvement of mixed nerves [Koller H, Kieseier BC, Jander S, Hartung HP. Chronic inflammatory demyelinating polyneuropathy. N Engl J Med. 2005;352:1343–1356].

Numb chin syndrome